Keyboard key not working: what to do

A key that stopped responding can have simple causes or require service. Before buying a new keyboard, run theonline keyboard test to confirm whether the fault is mechanical or just behavioural. This guide walks through the steps to investigate and what to try in sequence.

Confirm it's really the key

Open the tester page and press the affected key. If it doesn't light up, repeat the test in another browser and, if possible, on another computer. Keys that respond somewhere but not elsewhere usually point to drivers, user profiles or a remapped keymap rather than hardware failure.

Common causes

• Dust or debris under the keycap, blocking the electrical contact.
• Spilled liquid causing contact oxidation.
• Burnt mechanical switch, especially on older keyboards.
• Damaged or loose USB cable.
• Corrupted driver or bad update.
• Custom keymap applied by third-party software.

Things to try before service

1. Unplug and replug the keyboard (USB or Bluetooth).
2. Restart the computer.
3. Try a different USB port or another computer.
4. Remove the keycap and clean with compressed air.
5. On laptops, check whether the issue persists in the operating system's safe mode.
6. Update the keyboard driver or firmware.

When the issue is more serious

If the key is still dead after all this, the failure is likely in the membrane, switch or controller. On hot-swap mechanical keyboards, you can swap the single switch. On soldered boards or laptops, the repair usually means replacing the entire component. If the keyboard is old, compare repair cost with the price of a new one before deciding.