Laptop WiFi Not Working or Keeps Disconnecting? A Layer-by-Layer Guide from Software to Adapter and Antenna

WiFi not working: do not reinstall the system first. Tell the symptoms apart

"WiFi is broken" covers several completely different faults in everyday language. Reinstalling the system or the driver before you know which one you have is an easy way to go in the wrong direction and still end up with no connection. The first step is always classification: which symptom you see, whether it appeared suddenly or after an update, a drop, or a repair, and whether it affects only this machine or every device in the house.

Symptom comparison table

Symptom	What you see	First direction to suspect
Will not connect	The WiFi name appears, but entering the password fails, or the system says it cannot connect to this network	Wrong password, damaged saved network profile, driver, router settings
Connected but no internet	The WiFi icon shows connected, but web pages will not open, or the system says connected with no internet	The router itself has no internet, DHCP did not supply a valid IP, DNS problem
Keeps disconnecting	Drops after a while, needs manual reconnection or a restart to come back	Driver power-saving setting, interference, band or distance, router problem
Extremely slow	Connected, but pages and video load very slowly, while other devices are fine	Wrong band, interference, distance or obstruction, driver
WiFi icon gone	No WiFi option at all in the taskbar or in Settings	Airplane mode, hardware switch or Fn key switched off, wireless service stopped, driver or adapter gone
Airplane mode stuck	The airplane-mode icon stays on, will not switch off no matter what, or WiFi still does not come back after it is off	Airplane-mode switch, physical switch or Fn key, service or driver problem

When you record the symptom, write down four things, useful for repair or for asking for help: which of the six types above it is; whether it appeared suddenly or after an update, a drop, or a repair; whether it affects only this machine or every device in the house; and which steps you have tried, with what result.

Two common misunderstandings first. Signal bars do not equal speed. Bars only reflect signal strength, and channel congestion, interference, or a driver problem can leave the bars full while the speed stays very slow. Second, WiFi connected does not mean internet. Connected only means connected to the router. If the router itself has lost broadband, DNS is failing, or a public network needs a login page completed first, you get connected with no internet.

Layer-by-layer troubleshooting: software to hardware, no skipping

The rule: lightest first, one variable at a time, test immediately after each change, and write down before and after. If you change the driver, the DNS, and the router channel all at once, you will not know which change helped, and the next failure means starting over. The order below is software, settings, driver, hardware switch, then adapter and antenna.

Layer 1: software and basic settings

Three checks that change no settings: confirm WiFi is on and airplane mode is off; in the WiFi list, click Disconnect, wait a few seconds, then click Connect; run the built-in Windows network troubleshooter at Settings, System, Troubleshoot, Other troubleshooters, Network and Internet, Run. If the troubleshooter says it found nothing, that does not mean nothing is wrong. It only checks common settings. It will not detect a loose antenna or a congested router channel.

Forget the network and join it again: go to Settings, Network and internet, Wi-Fi, Manage known networks, pick the network, Forget, then go back to the WiFi list, pick it again, and re-enter the password. This targets a damaged saved profile or a password problem. Before you do it, make sure you know the WiFi password, or you cannot reconnect right away.

Power management setting, for repeated disconnections: in Device Manager, open the wireless adapter, Properties, Power Management, and uncheck "Allow the computer to turn off this device to save power", then restart and test. This only rules out the system switching the adapter off to save power. Unchecking it does not mean disconnections are fixed. Note that the Windows power plan and the maker's own power software may each have their own WiFi power-saving option, so do not stop after checking one place.

WLAN AutoConfig service, when the whole WiFi option has vanished: search for Services, open the Services app, find WLAN AutoConfig. Its status should be Running, and its startup type should be Automatic. If it has stopped, right-click it and Start it. If the startup type is Manual, change it to Automatic.

DNS, as a temporary test only: if other devices are fine and only this machine fails to open certain sites, check whether DNS was ever changed by hand. For the test, set the adapter back to obtaining DNS automatically, or remove manually added entries, and see whether it improves. Do not leave a DNS address copied at random in place long-term. After the test, restore automatic settings or the settings supplied by the router or provider. Do not believe that changing DNS makes the connection faster. Public sources only support that a DNS problem can stop pages opening, not that changing DNS equals faster speed.

Telling an IP problem apart: in Command Prompt, type ipconfig and look under Wireless LAN adapter Wi-Fi for the IPv4 address. If it starts with 169.254, Windows asked DHCP for an IP and got no reply, so the system assigned itself a link-local address, and that address cannot reach the internet. A normal home network should show 192.168 or 10 addresses, plus a default gateway. First run ipconfig /release, then ipconfig /renew. If it is still 169.254, check whether the router DHCP is working, and restart the router. This symptom does not mean the adapter is broken. DHCP switched off on the router, an exhausted address pool, a crashed router, or a wrong setting on the laptop can all produce the same symptom.

IP conflict: if the machine uses a manually fixed IP, and the router or another device uses the same IP at the same time, they conflict, showing as intermittent disconnection or connected with no internet. Check at Settings, Network and internet, Wi-Fi, the network properties, whether the IP setting is Manual. If it is Manual, change it back to Automatic (DHCP) and test. If a fixed IP is genuinely required, confirm it sits outside the router DHCP range, or that it has been reserved on the router.

Network reset, a heavier step, know the consequences first: go to Settings, Network and internet, Advanced network settings, Network reset, Reset now, confirm, and the computer will restart. It removes and reinstalls the network adapters and restores many network components to defaults. Saved WiFi networks will be forgotten, so you must re-enter passwords afterwards, and VPN adapters and manually set IP or DNS may need setting up again. Before doing it, write down the WiFi password, VPN settings, and manual IP and DNS. Do not run a network reset on a machine with no internet at all before backing up the driver. If the driver does not reinstall itself afterwards, downloading a driver gets much harder.

Command reset, administrator rights required: in the taskbar search, find Command Prompt, right-click, Run as administrator, then type each line in turn, pressing Enter after each: netsh winsock reset, netsh int ip reset, ipconfig /release, ipconfig /renew, ipconfig /flushdns. Restart the computer before testing. In plain terms, flushdns clears the local DNS cache so the system asks the DNS server again; release gives up the IP address it currently holds; renew asks the router for a new IP address; winsock reset resets the Windows communication layer settings; int ip reset resets the TCP/IP settings. Do not run a block of commands copied from the internet if you do not understand what each one does.

macOS checks: first confirm WiFi is on, switch WiFi off and on once, wait about 30 seconds before switching it back on, and restart the Mac and the router separately, noting which step helped. Temporarily switch off VPN, firewall, antivirus, and content-filter apps and test again, remembering to switch them back on afterwards. To forget a network, go to System Settings, Network, Wi-Fi, find the network in known networks, choose Forget This Network, confirm, then join it again and enter the password. Apple's own guidance says forgetting a network deletes that network and its password. For Wireless Diagnostics, hold the Option key, click the WiFi icon, choose Open Wireless Diagnostics, and follow the on-screen instructions. This tool does not change network settings. When the diagnosis finishes it gives a summary and suggestions. If you need to watch a disconnection happen, you can use its monitoring function. For Location, creating a new network location tests with a fresh set of network settings without deleting the original Automatic location, and you can switch back at any time. The path is System Settings, Network, the Action pop-up menu, Locations, Edit Locations, add with the plus button, name it, Done. To renew a DHCP lease, go to System Settings, Network, Wi-Fi, Details, TCP/IP, Renew DHCP Lease. For DNS, go to System Settings, Network, Wi-Fi, the network Details, the DNS tab, where you can add with plus or remove a problem entry with minus, and for a test you can switch back to automatic. If the WiFi option has vanished entirely, no network connects at all, and every software step has failed, you can run Apple Diagnostics to check the internal wireless hardware. Apple's own guidance says Apple Diagnostics can diagnose internal hardware, including the logic board, memory, and wireless components. Do not present an NVRAM or SMC reset as a WiFi repair step. Apple support documents do not list them as WiFi repair methods, and Apple silicon models have no traditional SMC reset procedure at all.

Layer 2: driver

How to open it: press Win plus X, Device Manager, expand Network adapters, and find the wireless adapter. Its name usually contains Wireless, Wi-Fi, WLAN, or 802.11, or a maker name such as Intel, Realtek, MediaTek, or Qualcomm.

Action	When to use it	Key steps
Update driver	Driver suspected old or damaged	Right-click the adapter, Update driver, Search automatically
Roll back driver	The fault appeared after an update or a system update	Adapter, Properties, Driver tab, Roll Back Driver. If the button is grey, there is no older version to roll back to
Uninstall and reinstall	Update and roll back both failed	Adapter, Uninstall device, restart the computer, let Windows reinstall it automatically
Disable and re-enable	Adapter failing intermittently, suspected temporary fault	Adapter, Disable device, wait a few seconds, Enable device

Pick one of the four driver actions, not all four at once, or you will not know which one helped. Before uninstalling a driver, download the correct driver on another device as a backup, because after uninstalling, the machine may have no internet at all, and finding a driver then is much harder. If Windows does not reinstall it automatically, use another device with internet to download the driver for that exact model from the laptop maker's official support page, copy it over on a USB stick, and install it.

Driver sources: official only. Drivers should come only from the laptop maker's official support page, searched by exact model, Service Tag, or serial number, or from the adapter chip maker's official page, such as Intel. Do not use third-party driver-downloader sites. Do not use a one-click repair tool of unknown origin. Public sources consistently point to the maker's official support page plus the chip maker's official page as the driver sources. Third-party tools may install the wrong driver, bundle extra software, or introduce a security risk. Intel's official guidance notes that some OEM systems use customised drivers, and the maker version may differ from the Intel reference driver. If unsure, use the laptop maker's version first.

Reading driver status flags: in Device Manager, a yellow exclamation mark on the adapter means a driver or device problem. A downward arrow means the device has been disabled, so right-click it and Enable device. If the wireless adapter is missing entirely, first click Action, Scan for hardware changes, and see whether it appears. If it appears under Other devices as Network Controller, the driver is not installed or not recognised. If the device status says Windows has stopped this device because it has reported problems, the suggested order is restart, update the driver, roll back the driver, uninstall and restart to let Windows reinstall, then check Windows Update. If all of that fails, only then consider a hardware possibility.

Practices not recommended: registry-editing tricks found online, such as changing a RadioEnable value, are high-risk unofficial practices. Microsoft does not list them as standard troubleshooting steps, and a wrong edit can leave the system unstable or unable to start. Do not try them. On macOS, deleting .plist files from the SystemConfiguration folder is likewise unofficial, so do not try that either.

Layer 3: hardware switch, Fn key, BIOS

Physical switch: some laptops, especially older models, have a physical WiFi switch or slider on the side or front edge. Switched to OFF, it turns the whole wireless function off, and Windows Settings will show no WiFi option either. Check carefully along the sides and front edge for a switch with a WiFi icon, and if there is one, confirm it is set to ON. On some models, a side slider set the wrong way locks airplane mode on, and no click in system settings will switch it back.

Fn plus F key, varies by brand and model: many laptops switch WiFi or airplane mode with Fn plus one of the F keys, and that key usually carries a WiFi or airplane icon. Which key it is varies by brand and model, so never write it as the same combination for every laptop. Tell the reader to look at the key on their own keyboard that carries the icon, try it with Fn, and check the brand's official manual or support page for that model's combination. Common examples are examples only, never a general rule: HP commonly uses F12 with a wireless icon, and on some models an orange or red light means off; ASUS commonly uses Fn plus F2, on some models the airplane-mode key; Dell commonly uses F2 or another F key with a WiFi icon; Lenovo newer models commonly use Fn plus F5 or Fn plus F7. In every case, the keyboard icon is the authority. If the Fn combination does nothing, the keyboard hotkey driver may not be installed, and the matching driver must be downloaded from the brand's official support page for that model.

WLAN switch in BIOS: BIOS can switch the wireless adapter off entirely. If it is off in BIOS, Device Manager in Windows will not show the adapter at all, and no amount of driver reinstalling will help. The general check is to restart, press the key shown on the boot screen to enter BIOS, look for Wireless, WLAN, Connection, or Integrated Devices options, confirm WLAN or Wireless is set to Enabled, save, and exit. The key to enter BIOS varies by brand, commonly F2, F10, Del, or Esc, and the boot screen usually shows it. Never write one key as universal. Warning: do not change other settings in BIOS that you do not understand. Check only the WLAN option. If unsure, do not change anything, and save before exiting. Check BIOS only when Device Manager shows no adapter at all, driver problems have been ruled out, or someone has changed BIOS settings. Do not make a BIOS check the first step.

Airplane mode stuck, three layers: first, the system switch, at Settings, Network and internet, Airplane mode, off, or in the taskbar Quick Settings. Second, the physical switch or Fn key, as above. If the physical switch is set to airplane mode, the system setting may not switch it back. Third, the service and driver layer: check the Radio Management Service startup type and status, disable and re-enable the WiFi adapter in Device Manager, and try a network reset.

Layer 4: adapter, antenna, and cable fault signs

All of the following are suspicions, not diagnoses. A diagnosis needs the machine opened for inspection or professional testing. Do not conclude the adapter is broken and must be replaced on one sign alone.

Sign	Why it points at hardware
Device Manager shows no adapter at all, not even under Other devices or hidden devices	BIOS may have switched it off, the adapter may be loose or poorly seated, or the adapter itself may have failed
Device Manager shows the adapter with a yellow exclamation mark, and reinstalling the driver does not help	Driver-to-hardware communication failing, possible hardware fault
Adapter appears and disappears intermittently, back after a restart, then gone again	Poor contact, cable or slot problem, or an intermittent adapter fault
WiFi icon and option entirely gone, while airplane mode, Fn key, service, and driver are all normal	A hardware problem with the adapter needs considering
Mac shows Wi-Fi: No hardware installed	A WiFi card hardware problem is a strong suspicion, and authorised repair is the right step

Antenna and cable fault signs, with the key test being weak even next to the router: if the laptop sits right next to the router and the signal is still extremely weak, the speed extremely slow, or the connection keeps dropping, while other devices in the same spot show a normal signal, suspect that the internal antenna cable inside the laptop has come loose or been damaged, rather than a simple router coverage problem. In principle, the laptop's internal WiFi antenna usually runs by cable and coaxial line from the base through the hinge to the screen bezel. Long-term hinge movement, a drop, or a past disassembly can squeeze, loosen, or damage the cable, leaving the signal far weaker or intermittently dropping. A WiFi problem that appeared after a drop, impact, disassembly, SSD replacement, or screen replacement is a strong reason to note which disassembly it followed and to tell the repairer.

Do not open the machine to check the antenna yourself: the antenna cable is very thin and its connectors are very small, so opening the machine yourself can easily snap the cable or damage other parts. Opening the machine carries its own risks, including static discharge, a broken cable, lost screws, and failing to reassemble it. If an antenna problem is suspected, send it in for inspection. Do not write that any particular signal-strength figure proves the antenna is broken, because signal strength depends on environment, router, and antenna placement together, and no single threshold can diagnose it.

Router or laptop: four comparison tests

This is the most important judgement in the whole article. Do not tell a user to reinstall the system or send the machine in before the responsibility has been separated. Change only one variable at a time, and test immediately after each change.

Test	How to do it	How to read the result
Other-device test	Use a phone or tablet on the same WiFi, open two different websites, and play a short video. Do not judge by the WiFi icon alone	Another device online normally means the router and upstream are most likely fine, and the fault is more likely in the problem laptop
Phone hotspot test	Let the laptop join the phone hotspot, and test whether it can get online, confirming the phone itself has mobile data and internet	Laptop fine on the hotspot but not on the home WiFi: focus on the home router settings, saved profile, and compatibility. Laptop also fails on the hotspot while other devices are fine: focus on the laptop adapter, software, and hardware
Wired test	Connect the laptop to the router with a network cable and test	Wired fine and wireless not: the wireless side is the strong suspect. Wired also failing: the router, broadband, or laptop network settings are suspects
Close-range test	Walk to right beside the router and connect, and see whether it connects and whether it drops	Works beside the router and drops far away: check coverage, interference, and band first, and do not run a factory reset at once

Notes: a phone reaching the internet on mobile data does not mean the phone WiFi is fine. To test the phone WiFi, test the phone on WiFi, not on mobile data. The phone hotspot test is only a change-of-network test, not an absolute standard. The hotspot itself is affected by the phone signal, the phone settings, and data limits.

Restarting the router, the correct way: unplug the router power, wait about 30 seconds, plug it back in, and wait until the router has fully started and its indicator lights have returned to normal before testing again. If the router and the modem are separate, restart both, and wait for the upstream to sync. Restarting is not resetting. Do not press the Factory Reset or reset button on the router unless you are ready to set the router up again. A reset clears the WiFi password and every custom setting. Do not press the reset hole on the router body by mistake.

Router versus laptop responsibility table

Symptom	More likely responsible side	Next step
Every device cannot get online	Router, broadband upstream, provider	Restart the router and modem, and ask the provider whether there is a fault
Only this laptop cannot get online, other devices fine	The laptop itself	Work through the software, settings, driver, and hardware-switch checks in order
Laptop fine on the phone hotspot, not on the home WiFi	Home router settings, saved profile, compatibility	Forget the network and reconnect, try another band, check the router settings
Laptop fails on every WiFi, other devices fine	Laptop adapter, software, or hardware	Driver, USB adapter comparison, hardware-sign checks
Fine near the router, drops far away	Coverage, interference, band	Change band, reduce obstructions, check the router position

2.4 GHz versus 5 GHz, a qualitative comparison with no absolute speed figures: 2.4 GHz penetrates walls better and covers a longer distance, but it is more easily disturbed, with many devices on the same band. Neighbour WiFi, Bluetooth devices, and microwave ovens can all cause interference, showing as intermittent disconnection or fluctuating speed. 5 GHz is faster and less disturbed, but it penetrates walls worse and covers a shorter distance. Far away with walls in between, a 5 GHz signal falls fast, and that does not mean the adapter is broken. First walk closer to the router and switch to 2.4 GHz before judging. If the router gives 2.4 GHz and 5 GHz separate names, try the other band and see which is stable. If the router uses Band Steering or Smart Connect to allocate bands automatically, some older devices may connect unstably. You can consider splitting the two bands into separate names in the router settings and choosing by hand, following the router maker's instructions. On channels, the 2.4 GHz band congests easily. You can use a WiFi scanner to see which channel nearby networks use, then switch to a less-used channel and test. Never write that switching to a particular channel is always faster. The least-disturbed channel differs by environment. Do not teach readers to change advanced router settings at random, such as bandwidth, encryption mode, or transmit power. A wrong change can leave every device in the house unable to connect. On router position, walls, floors, metal objects, and large appliances all weaken the signal. A router should sit centrally, higher up, and away from metal and large appliances. On router firmware updates, follow the router maker's official guidance, and do not use third-party firmware.

Temporary ways to get online while waiting for repair

USB WiFi adapter: a small adapter that plugs into a USB port and lets the laptop connect to WiFi through USB. It is one of the fastest and simplest temporary options, useful when the built-in adapter is suspected faulty, the driver is not fixed yet, or internet is urgently needed. To install it, plug the USB adapter into a USB port. Windows usually installs the driver automatically. If it does not, follow the product instructions and download the driver for that model and Windows version from the maker's official website. After installing, pick the network in the WiFi list and enter the password. If Windows keeps using the old built-in adapter, disable the old built-in adapter in Device Manager so Windows uses only the external adapter. Notes: use only the product maker's official website for the driver, never a third-party driver download site. Before buying, confirm it supports your operating system version and bands. Some products do not support macOS, so read the product notes before buying. This article recommends no particular model. Try another USB port to rule out a faulty USB port, and test plugged directly into the machine USB port rather than through a USB hub first. A USB adapter is a temporary replacement, not a repair of the built-in adapter. If the built-in adapter or antenna has a hardware problem, the machine still needs repair.

Using the USB adapter as a responsibility test: when the built-in adapter will not connect, plug in the USB adapter, install its driver, and join the same WiFi. External connects and built-in does not: the built-in adapter, antenna, or built-in driver is the strong suspect, and at the same time this proves the router and broadband are not entirely down. External also fails: do not conclude at once that the built-in adapter is broken. Check the router, the USB port, the system settings, and driver conflicts again, for example both adapters enabled at once causing a conflict. This comparison only points a direction. It cannot be written as a diagnosis of which part has failed, because only opening the machine for inspection can confirm that.

Phone hotspot and USB tethering: switch on the phone hotspot and let the laptop join it, for testing and temporary internet. Connecting the phone to the laptop with a USB cable and switching on USB tethering on the phone shares the phone mobile data over the cable, which suits a case where WiFi fails entirely but the phone signal is normal. Watch the phone data usage and battery. Long sharing sessions heat the phone and drain it.

LAN cable, wired direct connection: if the laptop has a LAN port, or you have a USB-to-LAN adapter, connect a network cable straight to the router. That restores internet at once, and it is also the wired comparison test described above. Wired fine and wireless not: the wireless side is the strong suspect.

Danger red flags: if any of these appear, stop at once

If any of the following appears, do not try power-on tests again, do not repeat plugging and unplugging, and do not open the machine yourself.

• Liquid inside the machine: if water or a drink got in and WiFi then fails, do not test it with power. Stop using it and send it in. Powering on after liquid exposure can widen a short circuit and the damage.
• Burning smell, smoke, or abnormal heat: a burning or plastic smell from anywhere on the body, smoke, or one spot abnormally hot to the touch. Unplug the power at once, switch off, stop using it, and send it in. Do not put a machine that smells strange or smokes into a sealed bag or bedding.
• WiFi fault after a drop or impact: the inside may already be structurally damaged. Do not open the machine to test it yourself.
• Problem appeared after the machine was opened: disassembly may have disturbed a cable, the antenna, or the adapter. Do not open it again to fix it yourself. Tell the repairer honestly whether it has been opened, and do not hide it.

The rule: unplug the power at once, and switch off if you can do so safely. When sending it in, describe the exact red-flag symptom, so it can be given priority.

When to send it in, and what to prepare

Consider repair, rather than continuing to reinstall the system or open the machine, if any of these fits: Device Manager shows no adapter at all, BIOS has confirmed WLAN is enabled, and reinstalling the driver does not help. The adapter disappears intermittently, comes back after a restart, then disappears again. The signal is extremely weak and keeps dropping even right next to the router, while the USB adapter test works normally, pointing at the built-in adapter or antenna path. An antenna cable is suspected loose or damaged, for example after a drop, or after the hinge developed a noise or looseness. Apple Diagnostics reports a WiFi hardware problem. Airplane mode is stuck, the physical switch and Fn key have been confirmed fine, the system setting will not switch back, and a network reset does not help. A Mac shows Wi-Fi: No hardware installed, and basic restart, forgetting the network, and Wireless Diagnostics still do not help.

Do not try these again: do not reinstall the system to fix WiFi, because a hardware fault survives a reinstall. Do not use a third-party driver tool for a one-click repair, because drivers should come from official sources. Do not edit the registry, and do not delete system configuration files. Do not open the machine to check the antenna or cable. Do not press the router Factory Reset button.

Preparation checklist before sending it in: write down the symptom, using the six types above. Write down when it started: sudden, after an update, after a drop, after a disassembly. Write down the steps you tried, with results, for example tried forgetting the network, reinstalling the driver, and restarting the router, with other devices normal. Do not write tried everything. Write each step out. Write down the comparison test results: other devices, phone hotspot, wired, and close-range tests. These are the most important pieces of separating evidence. Bring the machine with its charger. The repairer needs to power it on and test, and the charger rules out power-related interference. Write down the WiFi password, in case the repairer needs to test a connection. Without it, the repairer cannot reproduce a connection problem. Back up important data. Backing up before repair is general good practice, because the repair process may require reinstalling the system or replacing a part. Do not open the machine yourself. Opening it may worsen the problem and may affect later inspection. When sending it in, describe symptom plus time plus steps tried plus comparison results. Do not say only WiFi is broken, and do not say I read online that a particular part must be broken. The repairer needs to test it directly. Your job is to supply accurate symptoms and steps tried.

Pricing reference

For pricing, the confirmed figures are: battery replacement from HK$580, screen replacement from HK$1,280, motherboard chip-level repair from HK$880, and keyboard replacement from HK$480. WiFi repairs have no confirmed price, and are always quoted in writing after inspection. For pricing details, see our pricing. To book an inspection, go to diagnostic and leave your details.

Shop address: Room 1209, Dalton Plaza, Shek Mun, Sha Tin. Phone: +852 2186 8010. WhatsApp: +852 6558 6806. Opening hours: 12:00–19:00.

Frequently asked questions

Q1: The laptop connects to WiFi but web pages will not open. Does that always mean the laptop is broken?
A: Not necessarily. Split it into two layers. First, does the router itself have internet? Can a phone or another computer on the same WiFi get online? If not, the router or broadband side is the strong suspect. Second, only this machine fails while other devices are fine, so the laptop side is the strong suspect, and driver, DNS, IP, VPN, firewall, or security-software interference are all possible. Run the other-device test and the phone hotspot test before judging.

Q2: After a Windows update, the WiFi icon disappeared. What should I do?
A: First check whether airplane mode, the physical switch, or an Fn key was pressed by mistake, then open Device Manager and see whether the adapter is still there and whether it carries a yellow exclamation mark. A fault that appeared after an update makes rolling back the driver a reasonable next step. If the roll-back button is grey, there is no older version to roll back to, so try uninstalling and restarting to let Windows reinstall the driver. Before uninstalling, download the correct driver on another device as a backup. If all of that fails, check in BIOS whether WLAN is enabled.

Q3: It only connects right next to the router and drops a little further away. Is the adapter broken?
A: Not necessarily, and not necessarily a fully broken adapter. First try switching to 2.4 GHz, because 5 GHz penetrates walls worse and covers a shorter distance, and a signal falling fast with distance and walls does not mean the adapter is broken. Then check the router position, obstructions, interference, and channel congestion. If the signal is extremely weak and keeps dropping even right next to the router, while other devices in the same spot are normal, suspect that the internal antenna cable has come loose or been damaged. Do not open the machine yourself in that case. Send it in for inspection.

Q4: Plugging in a USB adapter gets me online. Does that mean it is fixed?
A: No. A USB adapter is a temporary replacement and a separating tool. It proves the router and broadband are not entirely down, and it points at the built-in adapter, antenna, or built-in driver as the strong suspect. The built-in problem itself is not solved. If you keep needing the external adapter to get online, send the machine in for the built-in part to be inspected.