Still Locked After the Basic Reset? Advanced BIOS Password Guide: Brand Differences, Why CMOS Clearing Fails, Chip-Level Risks, and the Inspection Checklist

Premise: This Is the Advanced Article, Not a Rewrite of the Basics

The earlier article, "Forgot BIOS Password / Can't Enter BIOS: Three Password Types, Official Unlock Methods for Five Brands, and When It Must Go to a Repair Centre", already covered the basics: what the three password types each lock, why removing the CMOS battery may not clear the password, the official approach for each of the five brands in outline, and which situations must go to a repair centre. This article only cites that article here as a premise and does not rewrite that basic content. It assumes you have already done the basic methods: you have identified which password the screen is asking for, tried the official route suggested for your brand, tried a full shutdown and restart, and tried removing the CMOS battery or clearing CMOS, yet the machine is still locked.

The single principle of this advanced article is: classify first, then act. Brand, series, password type, whether the screen shows a code, whether you remember a higher-level password, which clearing method you have already tried, and whether the machine belongs to a company or a school, all change the next step. Without hands-on inspection, any cause is only a possibility, not a diagnosis, and where the evidence is uncertain this article says "may" and notes that hands-on inspection is needed. There is no confirmed price for BIOS unlocking itself, so it is quoted in writing after inspection throughout, and this article gives no specific BIOS unlocking figure.

Step 1: Ask Seven Questions First, Because a Wrong Classification Makes Everything After It Wrong

After the basic methods, the first step is not to remove the battery again, but to classify the case with the seven questions below. Many advanced cases stall not because there are too few methods, but because different layers of lock are treated as the same thing, or a desktop method is applied to a laptop, or an old-machine method is applied to a new machine.

Classification question	Why the answer changes the next step	What goes wrong if it is answered wrongly
Brand and series	Dell, HP, Lenovo, ASUS, and Acer have completely different official routes, and within one brand the consumer and business lines differ too	The wrong brand route wastes an official application
Which password the screen asks for	The power-on password, the administrator or supervisor password for entering BIOS, and the hard-drive password have completely different official outcomes	Unlocking the BIOS password is mistaken for recovering hard-drive data
Whether you remember a higher-level password	In Lenovo cases, remembering the supervisor password is itself an officially recognised clearing route	A machine with an official route is taken apart for no reason
Whether the screen shows a code	The Dell error code, the halt code on older HP consumer machines, and the no-halt-code behaviour of HP business machines each point to a different next step	A code is copied wrongly, or a code is handed to a third-party generator when there is none
Whether the machine has a jumper or a removable battery	Dell desktops have a PSWD jumper, laptops do not, and some laptops have no separate RTC battery at all	A method with nothing to work on is tried again and again
Which clearing method has already been tried	A jumper, battery removal, and the power-button RTC reset are three different operations with different effects	An RTC reset is mistaken for a CMOS clear
Whether proof of ownership is complete	The Dell release-code process expressly requires proof of ownership, and a second-hand machine without documents will hit that barrier in the official route itself	An official application is refused, and only then is the missing proof discovered

Write the seven answers down before reading the brand sections. On inspection, that classification sheet itself is the most useful information you can bring.

Dell Advanced: The Desktop Jumper Route and the Laptop Release-Code Route Are Completely Different

Dell official documentation divides BIOS passwords into three kinds: the System Password, which blocks booting; the Setup or Admin Password, which blocks changing BIOS settings; and the Hard Drive Password, which locks the drive and its data. The document says the same method can clear all three, but also warns that the interface varies by model and that the service manual for that machine governs. That warning is the key advanced point: a general document cannot override a model-specific manual.

Dell route	Applicable machines	Key points and limits
PSWD jumper clearing	Most Dell desktops; laptops have no jumper	Follow the service manual to find the jumper marked PSWD or PASSWORD; this method also clears the system, setup, and hard-drive passwords, but it does not clear the Windows login or online account passwords
RTCRST jumper combination	Desktops only, in a separate Dell official CMOS document	Remove the PSWD jumper cap, move the cap to the RTCRST jumper, apply power for 10 seconds, then move it back to PSWD; the document notes this method also clears BIOS-level passwords
Password Release Code	All Dell computers, and the only official option for laptops or machines without a jumper	Enter the wrong password 3 to 5 times until an error code appears; copy the error code exactly; contact Dell Technical Support; provide the error code and proof of ownership; after verification Dell provides a release code to enter at the password prompt
Battery reseat method	Desktops and laptops, in the Dell official CMOS document	Shut down, disconnect power, disconnect the main battery if possible, open the case, find the small coin battery, disconnect it, hold the power button for 10 to 20 seconds, then refit it; the document notes this method also clears the BIOS password, and after booting the machine will usually ask you to reset the date and time

The figure of 3 to 5 wrong entries needs to be stated carefully. In the Dell process, the number of wrong entries is not simply a punishment mechanism, but the trigger that produces the unlock code, and a miscopied code makes the later application invalid. That figure belongs only to this Dell process; it is not a universal trial limit, and this article gives no universal trial-limit figure, because no official universal figure exists.

There are two further Dell advanced traps. First, the Dell official FAQ states plainly that not every hard-drive password can be reset by Dell, and in particular Dell cannot make a password release code for an NVMe SSD. The advanced article must keep the BIOS password and the NVMe or hard-drive password separate, and must not imply that the release code works for everything. Second, the Dell general CMOS document says battery reseat also clears the BIOS password, but an iFixit reply on the Latitude 5540 says that even disconnecting both the main battery and the RTC battery, and returning the BIOS to defaults, still does not reset the BIOS password. Where the two conflict, the conclusion can only be that the service manual for the specific model governs, and neither statement can be taken as a general rule.

HP Advanced: Consumer and Business Security Levels Are Completely Different

HP is the brand where the consumer and business lines diverge most sharply. An HP employee replying in the official community to a ProBook case stated plainly that the BIOS password on ProBook or EliteBook machines is stored in dedicated non-volatile memory and "cannot be cleared by removing the CMOS battery or draining residual power"; the official suggestions were to contact HP Technical Support and, as a last resort, to replace the system board. Replies on the same business class repeat three points: business machines have stricter security settings than consumer models; business machines "do not generate a halt code"; and the password "cannot be derived from the serial number", because it is stored in non-volatile memory, so removing the RTC battery does not reset it.

HP situation	Screen and mechanism	Next step
ProBook or EliteBook business machine	Password stored in dedicated non-volatile memory; removing the CMOS battery or draining residual power does not clear it; business machines do not generate a halt code	Contact HP Technical Support; the last resort is system board replacement; prepare proof of ownership, such as the original receipt or invoice
Older consumer model	After repeated wrong entries at the password screen, a halt code or system disabled code may appear	The community approach is to press Enter 3 times first, or enter any password 3 times, copy the code shown, and then proceed; whether a halt code appears, and whether the code is purely numeric or another format, depends on the model
Any HP computer	HP has no universal master password that works for all HP computers, or even all models; the so-called universal password is a rumour	Do not trust a universal master password; removing or replacing the BIOS chip, removing the CMOS battery, or shorting the CMOS battery connector does not reset the password

The HP SMC.bin policy is in conflict, so only one safe wording is used. Earlier community posts still describe the SMC.bin process, under which HP once supplied a file called SMC.bin to users, used with a USB drive at boot to reset the password; but the same set of community posts also says that after April 2019 HP support no longer supplied that file, and without it the password cannot be cleared. That is a community-post claim, not the text of an HP official support document found in this research, and it contradicts the earlier SMC.bin instruction posts. This article therefore states that the official unlock route for HP business machines is governed by the latest reply from local HP support; it does not promise readers that SMC.bin can be obtained, and it does not present the old SMC.bin steps as a current general process.

There is one further community-level risk note, which must be labelled as not confirmed by an official document. Several HP community replies warn against removing the RTC battery before attempting the HP official SMC route, because removing the battery resets the clock, and the SMC file is said to be time-coded, so too large a gap between the system clock and the time inside the file may cause failure. This research found no HP official support document text confirming that claim, so it is listed only as a community-level risk note, not as an official warning.

Lenovo Advanced: The Supervisor Password Is the Watershed; Remembering It Opens a Route, Forgetting It Leaves No Official Clearing Procedure

The Lenovo official user guide states plainly that if you forget the supervisor password, "there is no service procedure to clear that password", and you must contact a Lenovo authorised service provider to have the system board replaced. Older manuals say the same and mention proof of purchase. That sentence is the watershed of the Lenovo advanced article: the question is not "is there a method", but "do you remember the supervisor password".

Lenovo situation	Official outcome
You remember the supervisor password and want to clear the power-on password or the system management password	At the boot logo screen press F1, enter the supervisor password to enter UEFI BIOS, in the Security or Password options put the supervisor password in the existing-password field and leave the new-password field blank, press Enter twice, then press F10 to save and exit, which clears that layer of password
You remember the supervisor password and want to clear the supervisor password itself	Clear it inside the BIOS menu; removing the CMOS battery does not clear the supervisor password
You forget the supervisor password	There is no service procedure to clear the password; contact a Lenovo authorised service provider to have the system board replaced
No supervisor password was set, and you forget the power-on or system management password	Contact an authorised service provider to clear it; do not assume battery removal will work
You forget a single NVMe password, or both passwords under a dual-password system	Lenovo cannot reset the password or recover the drive data; contact an authorised service provider to replace the drive; if the drive is a customer-replaceable unit, you may also buy a replacement yourself

A ThinkPads forum note on older models adds an important warning: the supervisor password can only be cleared inside the BIOS menu, and removing the CMOS battery does not clear it; moreover, if a supervisor password is set, removing the CMOS battery means every boot first shows the supervisor password prompt until the correct password is entered and the date and time lost through the power loss are reset, or booting cannot continue. The older-model power-on password is different from the supervisor password, and according to that forum, disconnecting all power for a period may make it disappear, but only if no supervisor password is set. That explains exactly why some people feel the machine got "worse" after removing the battery: what they removed was only the clock, while the lock itself never moved.

ASUS Advanced: Only a Remembered Old Password Allows a Change; Forgetting It Leaves Only the Official Support Route

The ASUS official FAQ draws a clear line between two situations. If you remember the old password, you can change or delete the password inside BIOS; if you forget or lose the BIOS password, ASUS states that the BIOS or Security password is the user's personal information, which ASUS systems do not collect, so you must contact ASUS product support or an ASUS authorised repair centre for help. A motherboard-class FAQ says the same: changing the Administrator Password or User Password requires entering the old password first; to clear it, leave the new-password field blank and press Enter directly; press F10 to save afterwards. In other words, the official route offers no option to "delete the password without the old password".

ASUS situation	Official approach
You remember the old password and want to change or delete it	With the machine off, hold F2 and press the power button to enter BIOS, except on handheld gaming devices, where the volume-down key plus the power button is used; press F7 or choose Advanced Mode; go to the Security page and choose the password to change; enter the old password and the new password; to clear it, leave the New Password field blank and confirm; finally press F10 to save and exit; steps may vary slightly by model
You forget or lose the BIOS password	Contact ASUS product support or an ASUS authorised repair centre for help; because ASUS systems do not collect that password, there is no self-service recovery route
Repeated wrong BIOS passwords at boot temporarily disable further input	This is a built-in anti-guessing safety mechanism, and the screen may show a warning; the ASUS official advice is to press the power button to shut down, then boot again to enter the password again, and to avoid entering wrong passwords repeatedly, or the lock mechanism will trigger again

A screen that locks at boot, or stops input after wrong entries, does not necessarily mean the password itself is permanently locked. Follow the official advice and do one complete shutdown and restart first, to confirm whether it is "temporarily locked input" or "the password is still wrong", before deciding the next step. That distinction must be written as a checking step, not as an unlock promise.

One server case must also be kept separate and must not be applied directly to laptops. The ASUS server product P12R-I official FAQ states plainly that, because of the hardware design, clearing CMOS RTC RAM does not reset the BIOS administrator password, and resetting that password requires a complete BIOS firmware reflash through the BMC web interface. That is a server product case, and server BMC architecture differs from laptop firmware architecture, so it must not be written as a laptop unlock method. Its only role in this article is to confirm that "clear CMOS equals clear password" has a counterexample at the official-document level; it is not a guide for laptop users to reflash firmware.

Acer Advanced: No Separate Official FAQ for New Machines, So the Default Route Is to Contact Local Support

Acer is the brand with the fewest public official FAQs among the five, and that gap itself is advanced information. An Acer Community official reply to a V3-471G case states plainly that the Acer Community does not provide BIOS password reset, recovery files, unlock codes, or instructions for bypassing BIOS security functions; even removing the CMOS battery or entering wrong passwords to generate a code will not be solved through the community; the password can only be removed through Acer official support channels. The same official community reply adds that you should contact Acer Support in your region or an Acer authorised service centre for help.

Acer situation	What can be written, and what must not be written
New machine, forgotten BIOS password	This research found no separate official FAQ page on the Acer official website for "forgotten BIOS password" on laptops; this article does not invent an Acer official FAQ link or steps, and the default route is to contact local Acer Support or an authorised service centre
Product support page maintenance note, for example the VN280G download page	That note states that you should not forget the BIOS boot password, that no software can reset it, and that if it is lost, the machine must go to an authorised Acer service centre for hardware repair; that statement is aimed at that product line and must not be generalised to all Acer models, although its direction matches the community reply
Older service manual, for example the TravelMate P633 series	The manual records a hardware gap for clearing the password on the board for some older models; that gap appears only in some older service manuals and does not mean new Acer machines necessarily have the same point or the same procedure; without the service manual for that model, do not short any two points on the board from memory, and always follow that model's service manual
Unlock codes or generators found online for Acer	This research found no Acer official page offering a laptop BIOS master-password generator or instant self-service unlock by serial number; third-party generator sites must not be written as an official method, and serial numbers or challenge codes must not be handed to sites of unknown origin

The Acer conclusion is short but important: the absence of an official FAQ does not mean the absence of an official route; the official route is a person, not a web page. When writing, it is better to write one fewer step than to add one unverified step.

Why Clearing CMOS Works on Some Machines and Not Others: Four Dimensions Decide

The ASUS motherboard official document defines Clear CMOS as clearing the RTC RAM inside CMOS, which holds the date, time, BIOS password, and BIOS setting parameters, and lists three methods: the Clear CMOS button, shorting the CLRTC pins for about 5 to 10 seconds, and removing the CMOS battery. Batteries come in two forms: a socketed coin battery, and a wired two-pin battery, where the two-pin connector is removed rather than the battery itself. Note that this is the definition in an ASUS desktop motherboard document, and it must not be applied directly to every laptop.

Dimension	Distinction	Why it decides success or failure
Where the password lives	RTC RAM, volatile memory kept alive by a battery, versus non-volatile memory or a dedicated security chip, which survives power loss	The former may disappear with power loss; the latter is unaffected by it; UEFI NVRAM generally sits on the same SPI flash chip as the firmware image and stores EFI variables, while old-style CMOS is battery-backed volatile SRAM that mainly keeps the clock and a small number of settings
Battery form	A socketed coin battery can be removed; a wired two-pin battery is disconnected at its connector; a soldered battery needs board-level handling and is not recommended for self-service; some machines have no separate RTC battery at all and rely on the main battery	For the HP Pavilion 17 series, for example, an iFixit reply notes that the series has no separately removable RTC battery, and the RTC voltage is supplied by DC power from the main battery; the suggested discharge method is to disconnect the main battery from the board and then hold the power button for 30 seconds; on such machines "remove the CMOS battery" has nothing to remove
Clearing method	A jumper or CLRTC pin, battery removal, and the power-button RTC reset have different effects	The Dell service manual lists items explicitly unaffected by the RTC reset, as shown below; doing an RTC reset and still seeing the password does not mean the machine is broken, only that the operation you did is not a password-clearing operation
Whether all power is disconnected	Removing only the RTC battery while the main battery stays connected to the board may leave residual power that makes the clear incomplete	This is a common operation-level explanation, offered as inference, and must be marked as depending on the model and the extent of disassembly; generally both the main battery and the RTC battery must be disconnected for a complete power-loss comparison

The Dell service manual on the RTC reset, meaning shutting down with the charger connected and holding the power button for 30 seconds, lists items explicitly unaffected, and that list is the most important distinction in the advanced article: a power-button RTC reset is not the same as battery removal or jumper clearing of CMOS, and the two must not be confused.

Items the Dell RTC reset does not affect	Meaning
TPM status	It does not clear or change the TPM status
Service Tag, Asset Tag, Ownership Tag	Machine identification data is not cleared
Admin Password, System Password, Hard Drive Password	All three BIOS or hard-drive passwords are unaffected
Key Databases, System Logs	Key databases and system logs are unaffected
Boot List, Secure Boot, Allow BIOS Downgrade	These depend on custom settings and are not uniformly unchanged

Putting the four dimensions together gives a checking-style advanced list, not a diagnostic promise: if the clock resets to zero after battery removal or Clear CMOS but the password prompt still appears, the password is more likely stored outside old-style battery-backed CMOS; if you can enter BIOS but cannot change settings and options are greyed out, that may be only User privilege, not proof that the Supervisor or Administrator password is cleared; if the machine asks for a password at boot and even the Boot Menu is unreachable, that is the power-on password layer and must not be confused with the Windows login password; and if the password prompt disappears but the drive is still locked, that is another layer of lock, as covered in the next section.

TPM, BitLocker, and the Hard-Drive Password: Unlocking the BIOS Password Does Not Necessarily Unlock Everything

The BIOS password, the hard-drive password, and the BitLocker recovery screen are three different layers of lock. Before you know which layer is locked, do not perform any operation that changes firmware or TPM state. The iron rule of this section is one sentence: separate the layers first, then act.

Lock layer	What it locks	Official direction if forgotten
Administrator or Supervisor password	Whether you can enter the BIOS setup program; only the Administrator can change or delete passwords	Follow the brand sections: Lenovo has an official clearing route when the supervisor password is remembered and no service procedure when it is forgotten; HP business machines follow the latest reply from local HP support
User password	Can be set after the Administrator password, and usually only allows booting without allowing changes to key settings	Insufficient privilege is not the same as an unlocked password; "can see BIOS options" must not be treated as "already unlocked"
Power-on password	A gate at every boot, with even the Boot Menu unreachable	Lenovo allows clearing inside BIOS when the supervisor password is remembered; other brands follow their own official channels
Hard-drive or SSD password	Locks the data on the drive itself, so moving the drive to another machine still leaves it unreadable without the password	A forgotten hard-drive password is often difficult to recover and may mean accepting data loss and replacing the drive; Dell states plainly that it cannot make a password release code for an NVMe SSD; Lenovo states plainly that it cannot reset the password or recover drive data
TPM plus BitLocker	Firmware or hardware changes may trigger the BitLocker recovery screen, asking for a 48-digit recovery key	A firmware upgrade, a board replacement with a new TPM, or disabling or clearing the TPM may all trigger recovery; pause BitLocker protection before the change and resume it afterwards; the key can be found in the Microsoft account; if the key is lost, the data must be erased and the system reinstalled

There is one further pre-inspection rule for BitLocker. If the machine has BitLocker, confirm before inspection where the recovery key is kept, including the Microsoft account, company IT, a paper copy, or a USB copy; if there is no key, state the risk first and do not assume the repair side can also unlock the encryption. For company machines, ask company IT where the key is kept, and do not assume it is the same as a personal account. If the key is found before inspection, note down where it is kept, and do not post the full key in any public place.

Chip-Level and EC-Level Unlocking: How the Principle Works, What the Risks Are, and Where the Boundary Lies

Chip-level or EC-level unlocking is not as simple as "read it out and write it back". The published tool principle is roughly this: a SOIC-8 test clip grips the SPI ROM chip, a USB programmer reads the whole flash image with flashrom as a backup, UEFI variable headers and known GUIDs are scanned to find the variable storing the password, that variable data is zeroed or marked deleted, and the modified image is written back to the chip. The tool itself warns that writing modified firmware may brick the device, that it should only be used on hardware you own, and that the original backup must be kept. Writing without an original image backup is not acceptable; that is the baseline.

Chip-level or EC-level point	Principle and boundary
When SPI NVRAM rewriting has a theoretical opening	Only when it has been confirmed that the password for that model really sits in a rewritable SPI NVRAM variable
What the EC is	The EC, or Embedded Controller, is a separate microcontroller handling power management, fans, the keyboard controller, and the battery interface; the EC has its own firmware, which may live on the same SPI flash chip, or in the EC itself, or in external flash; the EC usually connects to the southbridge or PCH over LPC or eSPI; the "BIOS chip" and the "EC" are not the same concept, so reflashing only the BIOS image may not address an EC-layer lock
Scope of the EC password evidence	Reverse-engineering research on Lenovo states that, on some models, the Supervisor password hash is stored through an EC-related mechanism over the LPC bus and that reading is locked after the boot stage; the researchers also state that the EC firmware itself was outside that study; that finding covers only the Lenovo mechanism in that study and must not be presented as the storage method for ASUS or Acer as well; this article only says "some models may involve the EC layer", never as a general rule
The dual-SPI-chip trap	A repair case notes that some pins of two SPI chips share the same data lines to the PCH; reading on-board without desoldering may return a mixed or wrong capacity, for example reading 8MB from a 4MB chip, and writing another machine's firmware image directly has caused bricking; model, chip capacity, the ME region, serial numbers, and other platform data may all affect the result
Possible effect of signed firmware	Signed firmware or Boot Guard-type mechanisms may make unsigned modified firmware difficult to trust and execute; but this research found no ASUS or Acer official document for laptop BIOS passwords stating their Boot Guard implementation details directly, so this point can only be written as "may be affected", not as confirmed by ASUS or Acer
Brick and after-effect risks	Any operation involving desoldering, shorting, or clipping an SPI chip carries risks of bricking, board damage, loss of serial number, MAC, or ME settings, and making later official repair more complex

The background of online "universal password or master password generator" sites also needs to be stated plainly. A technical article notes that such sites grew out of reverse engineering of old firmware checksum algorithms and once worked on old machines; but modern systems have gradually moved away from predictable checksum backdoors, and existing challenge-code mechanisms are mostly handled through official support channels, so for machines made in recent years the reliability of third-party generators is falling. This article recommends no specific generator site and does not ask readers to hand serial numbers or challenge codes to sites of unknown origin.

Anti-Theft Locks, Computrace and Absolute: Unlocking the BIOS Password Does Not Necessarily Unlock Everything

Unlocking the BIOS password does not mean Computrace or Absolute is unlocked; they are different layers of lock. Dell official documentation states that Absolute Persistence is the updated version of the old Computrace module; Absolute requires PKI authentication to the Absolute server before it can be fully activated; showing Enabled in BIOS only means the interface is ready to accept server activation, not that the function is already activated; only when Absolute software is installed in the operating system, the server issues a signed authentication and activation packet, and verification succeeds, does BIOS mark the persistence module as activated, after which that interface greys out; the effect of Permanently Disable is the same as the old Computrace Disable, after which that function can never be used again.

Computrace or Absolute status	How to read it
Deactivated	The better state in a second-hand inspection
Activated	A warning state; if Activated is shown but the seller cannot confirm that the company account is closed, there is a real risk
Disabled	Means only that it was never turned on, not that it was once activated and then removed
BIOS shows Enabled	Means only that the interface is ready to accept server activation, not that the function is already activated
Permanently Disable	An irreversible choice, which must not be suggested before machine ownership and the original organisation's intent are confirmed

A second-hand buying checklist notes that the Computrace, Absolute, or Persistence status should be checked in the BIOS Security area, and that a legitimately retired machine usually comes with asset disposal proof, an MDM removal screenshot, or confirmation that the Absolute account is deactivated. If the machine is itself a company or school asset, removing Computrace or Absolute requires account handling by the original organisation or Absolute, and locally clearing the BIOS password alone may not be enough; this article must remind readers to ask the original organisation first, and must not teach bypassing company asset management. If BIOS shows Computrace or Absolute as Activated, or the machine is suspected to be stolen or still under company management, stop and verify the source and the original organisation's removal status first.

When to Stop Trying: There Is No Universal Trial Limit, So the Stop Signals Are the Rule

This research found no Lenovo official document giving a universal BIOS password trial-limit figure, and no Dell or HP official document giving a universal clause such as "a permanent lock after a given number of wrong entries" or "locked for a given time". This article therefore does not write any unified figure such as "wrong a given number of times and the machine locks permanently". Instead, the stop conditions below apply: if any one of them appears, stop, copy the screen first, and only then think about the next step.

Stop condition	Why stop
The screen shows System Disabled, System Halted, System Locked, a halt code, or an error code	Copy all text and codes on the screen first, then shut down, and do not keep guessing; each extra attempt may turn a screen that says "can try again" into one that says "must restart before trying again"
A complete shutdown and restart, as ASUS officially advises, has been done, the password prompt still appears, and no possible password can be recalled at all	Stop and switch to official support channels, rather than relying on continuous guessing to trigger a longer lock
The screen shows System Disabled, a challenge code, or Unlock Key wording, but you are not the owner, have no proof of purchase, or the machine belongs to a company or school	Stop, do not hand the challenge code to a third-party generator site, and contact the owner, IT, or official support first
CMOS battery removal or Clear CMOS has been tried, the clock has reset to zero, but the password prompt is unchanged	Stop and do not disassemble repeatedly; that result itself is useful diagnostic information and should be recorded for the inspection side
You are unsure which layer is locked, or you have not confirmed where the BitLocker recovery key is	Stop, and do not reflash firmware, clear the TPM, or replace the board, all of which change TPM or firmware state
The machine can still be handled through official support, but you are already considering desoldering an SPI chip, shorting unknown board points, or using firmware images of unknown origin	Stop; chip-level work should be left to an inspection side that can back up the original image first and explain the bricking risk, not used as a first step
Computrace or Absolute shows Activated, or the machine is suspected to be stolen or still under company management	Stop, do not try to bypass it, and verify the source and the original organisation's removal status first
Before any operation, the original screen has not been photographed, the model and serial number have not been noted, and the importance of the data has not been clarified	Pause and make the record first; repeated attempts without a record only make it harder for the inspection side to judge

Two confirmed trigger figures are added here, and they must not be generalised into a universal limit: the Dell process uses 3 to 5 wrong password entries until an error code appears, after which the code is used to apply to Dell for a release code; on older HP consumer models, 3 wrong entries produce a system disabled code, while business machines may show no halt code. Those two figures belong to two brands and two processes, and they must not be merged into one sentence such as "three wrong entries locks the machine".

Before Inspection: Backups in Two Situations, Because a Fully Locked Machine Cannot Be Backed Up from Inside the System at Home

This backup section must start with a harsh premise, or it will mislead readers. If the machine already locks at boot and cannot enter Windows at all, readers at home cannot do an "enter Windows and back up" backup; at that point, so-called backup can only be pre-inspection records and risk disclosure, and must not be written as casually as "back up first, then send it in". This article must write two situations separately.

Situation	What can be done at home, and what cannot
Situation A: Windows can still be entered, for example only BIOS settings cannot be entered, but the system boots	Do a normal file backup first, then deal with the BIOS password issue; only after the backup is complete should any operation that changes firmware or TPM state be considered; also confirm where the BitLocker recovery key is kept
Situation B: Fully locked at boot, Windows cannot be entered	Do not remove the hard drive yourself, and do not reinstall the system yourself; a backup from inside the system cannot be done at home; first record how important the data is, and on inspection ask how the inspection side will handle the hard-drive data and whether BitLocker or TPM state will be touched; also state whether the drive has its own password and whether the data can accept reinstallation

The record list that applies to both situations is: a clear photo of the locked screen, including any error code, challenge code, or System Disabled wording, but the challenge code must not be posted publicly online; a list of methods already tried, including whether the CMOS battery was removed, whether Clear CMOS was done, whether a shutdown and restart was done, how many wrong entries were made, whether the Boot Menu can be entered, and whether Windows can be entered; a judgement of which layer is locked, covering whether the password appears at boot, only when entering BIOS settings, or as a hard-drive or BitLocker recovery screen; and for company or school machines, whether there is an IT department, whether MDM, Computrace, or Absolute is shown, and who the original organisation contact is.

Proof of Ownership, the Inspection Checklist, and Closing

Why official channels ask you to prove ownership has a direct answer: the BIOS password is itself a lock against theft and unauthorised changes, so no official channel can unlock it for anyone on the strength of a screen code alone. The Dell official BIOS password help page states that BIOS password recovery requires ownership verification, and you may be asked for the computer model, Service Tag, and account ownership, including proof of purchase or proof of ownership; for organisation-managed devices, contact the IT administrator; and if recovery is not possible, the board may need to be replaced. That point is used only to explain "why official channels ask for proof", and must not be written as proof that ASUS or Acer use exactly the same form; the actual requirements follow each brand's local support reply.

Information to bring or prepare for inspection	What to answer
The laptop itself plus its charger	Do not bring only the machine, because the inspection side needs the charger for boot testing
Full model name and serial number	From the sticker on the base; for Dell cases, the Service Tag as well
Purchase receipt or order record, if any	A second-hand machine without documents should be stated honestly, because the official route itself may be blocked for that reason
Photo of the locked screen	Including any error code, challenge code, or System Disabled wording; do not post it publicly online
List of methods already tried	Whether the CMOS battery was removed, whether Clear CMOS was done, whether a shutdown and restart was done, how many wrong entries were made, whether the Boot Menu can be entered, and whether Windows can be entered
Judgement of which layer is locked	Password at boot, password only when entering BIOS settings, or a hard-drive or BitLocker recovery screen, stated separately
Company or school machine information	Whether there is an IT department, whether MDM, Computrace, or Absolute is shown, and who the original organisation contact is
Data importance and BitLocker status	Whether BitLocker is present, where the recovery key is kept, whether the drive has its own password, and whether the data can accept reinstallation

Questions to ask proactively on inspection are: whether the password for this model can be handled through official support channels, or whether chip-level work or board replacement is needed first; whether the operation will touch TPM, Secure Boot, or BitLocker state; whether the original firmware image will be backed up first; if SPI or EC work is involved, how the bricking risk is described and what state the machine will be in if it fails; what Computrace or Absolute shows, and whether the original organisation must remove it first; whether inspection will test, item by item, entry into BIOS, entry into the Boot Menu, entry into Windows, and reading of drive data; and what records to take away, including which operations were done, which parts were replaced, and whether BIOS settings were changed.

The closing is three sentences. A machine still locked after the basic methods is not necessarily beyond help, but it does mean moving from "trying methods" to "classifying first"; with the classification done correctly, the official channel, chip-level inspection, and board replacement routes can be told apart and the right one chosen; with the classification done wrongly, removing the battery ten more times will only reset the clock while the lock itself never moves. BIOS unlocking itself is quoted in writing after inspection. For other repair price references, see pricing; to book an inspection, go to book an inspection. Shop information: Room 1209, Daly Plaza, Shek Mun, Sha Tin, phone +852 2186 8010, WhatsApp +852 6558 6806, opening hours 12:00-19:00.

Frequently Asked Questions

After getting a Dell error code, what should be done next?

Copy the error code exactly, contact Dell Technical Support, provide the error code and proof of ownership, and after verification Dell provides a release code to enter at the password prompt. The Dell process uses 3 to 5 wrong password entries until an error code appears, and a miscopied code makes the later application invalid. Hard-drive passwords must be handled separately, and in particular Dell cannot make a password release code for an NVMe SSD, so the release code must not be assumed to work for everything. BIOS unlocking itself is quoted in writing after inspection.

After removing the CMOS battery the clock resets to zero, but the password prompt still appears. What does that mean?

It more likely means the password is not stored in old-style battery-backed CMOS, but in non-volatile memory or in UEFI NVRAM on an SPI flash chip, which survives power loss. That result itself is useful diagnostic information, so stop and do not disassemble repeatedly, and record that result for the inspection side. The Dell service manual also lists explicitly that the power-button RTC reset does not affect the Admin Password, System Password, or Hard Drive Password, so still seeing a password after an RTC reset does not mean the machine is broken. Hands-on inspection is needed to confirm where the password is actually stored.

If the Lenovo supervisor password is forgotten, is there an official clearing procedure?

No. The Lenovo official user guide states plainly that if you forget the supervisor password, there is no service procedure to clear that password, and you must contact a Lenovo authorised service provider to have the system board replaced. That is completely different from the "remember the supervisor password" case, where the power-on password or system management password can be cleared inside UEFI BIOS by leaving the new-password field blank. The first step is therefore always to ask whether the supervisor password is remembered, and not to jump straight to disassembly. BIOS unlocking itself is quoted in writing after inspection.

A machine is fully locked at boot. Can it still be backed up at home before inspection?

No. Where the machine already locks at boot and cannot enter Windows at all, a backup from inside the system cannot be done at home, and the hard drive must not be removed or the system reinstalled by the owner. The correct approach is to record how important the data is first, and on inspection ask how the inspection side will handle the hard-drive data and whether BitLocker or TPM state will be touched, while also stating whether the drive has its own password and whether the data can accept reinstallation. If Windows can still be entered, for example only BIOS settings cannot be entered, a normal file backup should be done first, before dealing with the BIOS password issue. BIOS unlocking itself is quoted in writing after inspection.