You are halfway through an email when one letter stops appearing, or you open your laptop and nothing you type registers at all. The first thought is usually "it's broken, I'll need a repair." In practice, a large share of "dead keyboard" cases have nothing to do with failed parts. They come down to Filter Keys, Fn Lock, Num Lock, a confused driver or a dropped connection. At the same time, some keyboards really are broken, and no amount of settings tweaking will bring them back.
This guide shows you how to tell the two apart. First you narrow the cause by sorting your symptom into one of a few patterns. Then you check whether the key is actually sending a signal to the computer, which separates hardware from software. Finally, there are step-by-step fixes for laptop keyboards, wired mechanical boards and Bluetooth or wireless keyboards, with the usual sticking points noted at each step.
1. Sort the symptom first: one key, one row, everything, or only combinations
"My keyboard doesn't work" covers several problems with completely different causes. Pinning down which keys fail, and how, cuts the list of suspects by more than half. Find the row below that best matches what you see.
| Symptom | Most common cause | Hardware likelihood | Try first |
|---|---|---|---|
| A single key doesn't register (or types twice) | Debris under the keycap, worn switch contact | High | Remove the keycap and clean, confirm the signal with a key tester |
| Several keys in the same row or area die together | Broken trace in the key matrix, liquid damage | Very high | Test the same keys on another computer or in the BIOS screen |
| Nothing works at all | Lost connection, driver error, Filter Keys, flat battery | Low to medium | Restart, recheck the cable, receiver or pairing |
| Keys only register if held down, or respond late | Filter Keys (slow keys) turned on | Very low | Check whether right Shift was held for 8 seconds, turn the setting off |
| Numpad keys move the cursor like arrow keys | Num Lock off | None | Press Num Lock once |
| Letter keys type numbers (laptop) | Embedded numeric keypad turned on | None | Fn + Num Lock, or turn Num Lock off |
| F1 to F12 only change brightness or volume | Fn Lock state | None | Toggle Fn Lock, often Fn + Esc |
| Only the Windows key is dead | Win Lock on a gaming keyboard | None | Fn + Win or the dedicated lock button |
| One key drops out only when pressing two or three together | Rollover limit (ghosting) | Not a fault | Check the keyboard spec, use a different combination |
The pattern is clear: hardware is the likely culprit when specific keys or a specific area fail. When the whole keyboard misbehaves at once, a setting or connection change is far more likely than dozens of switches failing at the same instant.
2. Diagnosis step 1: check whether the key sends a signal at all
The most reliable dividing line is whether the computer receives the key press. A missing letter in Notepad is not enough to decide. Input method settings, shortcut conflicts or an app that intercepts certain keys can all swallow a character even though the key is working perfectly.
Using a browser keyboard test
- Open a keyboard test page in your browser and press every key once, working from the top left.
- A key that lights up on the on-screen keyboard is sending its signal correctly.
- Any key that never changes color is a key that sends no signal at all.
- Press suspect keys several times to see whether they respond only intermittently, or register twice for a single press.
How to read the result: if a key shows up in the tester but not in your document, the keyboard is fine and the problem lies with the program or input settings. If it never shows up in the tester either, the cause is the keyboard itself (switch, circuit or connection) or its driver.
Where people get stuck
- The Fn key is handled inside the keyboard and is never visible to a web page. Fn not showing in a tester is normal.
- Language-switch keys such as the Korean Han/Eng and Hanja keys, or Japanese IME keys, may not fire at all or may arrive as right Alt or Ctrl depending on the OS and browser. Check those by whether the input language actually switches.
- On-screen keyboards on phones and tablets do not send key codes, so they cannot be tested this way. Touch keyboard problems on a phone are outside the scope of this guide. If you connect a Bluetooth or USB keyboard to the phone, the same method works.
Use the BIOS screen as a second opinion
If some keys send no signal, restart and enter the BIOS (UEFI) setup screen, then see whether the arrow keys and Enter work there. The BIOS runs before Windows and its drivers load. If keys work in the BIOS but not in Windows, the cause is a driver or setting. If they fail in the BIOS as well, a hardware fault becomes much more likely. For an external keyboard, plugging it into a different computer gives you the same answer.
3. Diagnosis step 2: Windows settings and drivers, in order
If the whole keyboard is affected, or the keys worked in the BIOS, go through these checks in order. They are arranged from least to most effort.
1) Restart and try another USB port
Simple, but it fixes a lot. Keyboards often fail to reconnect after the PC wakes from sleep, and a full shutdown and restart clears it. For a wired keyboard, plug it straight into a port on the back of the PC instead of a hub or monitor port.
2) Turn off Filter Keys and Sticky Keys
Holding the right Shift key for eight seconds turns on Filter Keys, and pressing Shift five times in a row turns on Sticky Keys. Both get switched on by accident during games or when something leans on the keyboard. With Filter Keys on, short presses are ignored, which looks exactly like keys "not pressing" or needing to be held down.
- Windows 11: Settings > Accessibility > Keyboard, then turn off Filter Keys, Sticky Keys and Toggle Keys.
- Windows 10: Settings > Ease of Access > Keyboard, and turn off the same items.
- Sticking point: if it keeps coming back, also disable the keyboard shortcut option for Filter Keys so the same accident cannot repeat.
3) Check Num Lock, Fn Lock and Win Lock
These come from lock states on the keyboard itself rather than from Windows settings.
- If the numpad moves the cursor like arrow keys, Num Lock is off. Press it once so the indicator lights up.
- If a laptop without a numpad types numbers when you press keys like U, I, O, P or J, K, L, the embedded keypad printed on those keys is active. Turn it off with Fn + Num Lock (on some models Fn + F11, Fn + ScrLk or similar).
- If F1 to F12 only control brightness and volume, or the media keys stopped working, the keyboard is in the other Fn Lock state. Many laptops toggle this with Fn + Esc, and some use a "Function Key Behavior" option in the BIOS.
- If only the Windows key is dead on a gaming keyboard, Win Lock, a feature that prevents accidental presses mid-game, is on. Release it with Fn + Win or the dedicated lock button.
4) Reinstall the keyboard driver
If the keyboard stopped working right after a Windows update, the driver may be at fault.
- Right-click the Start button and open Device Manager.
- Expand "Keyboards" and look for a yellow warning icon.
- Right-click the device (usually "HID Keyboard Device" or "Standard PS/2 Keyboard") and choose "Uninstall device."
- Restart, and Windows reinstalls the driver automatically.
Sticking point: with a completely dead keyboard you cannot type into the search box. Use the mouse to go to Start > Settings > Accessibility > Keyboard and turn on the On-Screen Keyboard for temporary typing.
5) Check remapping tools and vendor software
If one key does something unexpected, a key remapping utility or a macro in the keyboard maker's software may be responsible. Close recently installed tools, or reset the profile to default in the keyboard software.
4. Laptop, wired mechanical or Bluetooth: what to check for each
The same "key not working" symptom points to different suspects depending on the type of keyboard.
| Type | Suspect first | What you can fix yourself | Signs it needs repair or replacement |
|---|---|---|---|
| Built-in laptop keyboard | Fn Lock, embedded keypad, driver, signs of liquid | Release lock states, reinstall driver, clean around keycaps | A whole row failing, symptoms after a spill, the keyboard deck bulging |
| Wired mechanical keyboard | Dust in switches, cable, USB port | Clean keycaps and switches, swap hot-swap switches, replace cable | Several switches failing at once, same fault on another PC, PCB damage |
| Bluetooth or wireless keyboard | Battery, pairing, channel switching, power saving | Replace batteries, re-pair, move the receiver closer | The same key still fails after charging and re-pairing |
When a laptop keyboard stops working
A laptop keyboard connects to the motherboard with a thin ribbon cable, and the circuit under the keys is laid out as a grid of rows and columns. When several keys along the same line die together, a single trace in that grid has most likely broken, and no setting will fix it. After a spill, keys often keep working for a few days and then fail as corrosion sets in.
Check the battery too. If the keyboard deck has lifted or the touchpad no longer clicks because the case is bulging, the battery may be swelling. Stop using the laptop and have it inspected by the manufacturer before treating it as a keyboard problem. Fn combinations and BIOS menu names differ between makers and models, so if the key combinations above do not match yours, look up your model on the manufacturer's support site.
When a wired mechanical keyboard stops working
Every key on a mechanical keyboard has its own switch, so "one key dead" and "one press types twice" (chatter) are common. Pulling the keycap with a keycap puller, blowing out the dust and pressing the switch repeatedly often brings it back. On a hot-swap board, swap the faulty key's switch with a working neighbor. If the problem moves with the switch, the switch is bad. If it stays in place, a socket pin is bent or the fault is on the PCB.
If the whole keyboard is dead, look at the cable and port first. Try a different cable on detachable models, and if the keyboard has a firmware reset combination, reset it as the manual describes.
When a Bluetooth or wireless keyboard stops working
Low battery is the most common cause. Before a wireless keyboard shuts off completely, it often drops input or lets only some keys respond late. Multi-device keyboards also look "dead" surprisingly often because the channel button has switched to another device, so check the channel first.
Next, re-pair it. In Windows, go to Settings > Bluetooth & devices, remove the keyboard and add it again. With a 2.4 GHz receiver, moving it from the back of the PC to a front port or a short extension cable closer to the keyboard reduces dropouts. If the connection drops after a period of inactivity, open the Bluetooth device's properties in Device Manager and, on the Power Management tab, untick "Allow the computer to turn off this device to save power."
5. When to treat it as a hardware fault, and what to do before repair
If any of the following apply, a hardware fault is more likely than a settings issue, and repair or replacement will usually save more time than forcing a DIY teardown.
- The same key stays dead in both a keyboard tester and the BIOS screen.
- An external keyboard shows the same dead key on a different computer.
- Several keys in the same row or area died at the same time.
- The problem started after liquid was spilled on the keyboard.
Before handing it in, take a screenshot of the keyboard tester result. It shows exactly which keys are not responding, which speeds up diagnosis and gives you evidence of the fault if the device is under warranty. While a laptop is waiting for repair, an inexpensive USB keyboard keeps you working.
6. Frequently asked questions
Q1. The tester doesn't show my language-switch key. Is it broken?
Probably not. Keys such as Han/Eng, Hanja or Japanese IME keys may not produce a key event at all, or may appear as right Alt or Ctrl, depending on the OS and browser. If switching input languages actually works in your documents, the key is fine. If it doesn't, check the keyboard and input method settings under Settings > Time & language > Language & region.
Q2. Some laptop keys don't work, but an external keyboard is fine. What does that mean?
If an external keyboard works, Windows and its drivers are generally fine, so the built-in keyboard hardware (circuit, cable or switches) is the likely cause. Fn Lock and the embedded keypad apply only to the built-in keyboard, though, so release those two first. If nothing changes, have it checked by a service center.
Q3. One key stops registering when I press two or three at once. Is that a defect?
Usually not. It is the keyboard's rollover limit. Many standard membrane keyboards drop certain keys in specific combinations, which is called ghosting. Hold the combinations you actually use in a keyboard tester. If a key drops out, change your key bindings or consider a keyboard with N-key rollover.
Q4. Can I use this method to check a phone's on-screen keyboard?
No. On-screen keyboards on phones and tablets do not send key codes the way physical keyboards do, so a keyboard test page cannot detect them. Fix those through the phone itself: clear the keyboard app's cache, update it or restart the device. If you connect a Bluetooth keyboard to the phone, everything in this guide applies.
7. Find dead keys in a minute with the keyboard tester
Every step in this guide comes back to one question: is there a key that sends no signal? Open the keyboard tester and press every key once. Keys that register stay highlighted and dead keys stay blank, so a faulty key is obvious at a glance. If no key stays blank but your document still won't type, the cause is a setting or input method, so work through section 3. If a specific key or row stays blank, treat it as hardware and follow sections 4 and 5.
The tester also lists every key held down at the same moment, so you can tell on the same screen whether a key only drops out in combinations because of rollover limits. It runs in your browser with no install or sign-up, and key presses are handled inside the page only, never sent anywhere.
