some keys are not working

Because the same group of letter keys—M, V, C, X, and Z—is consistently unresponsive, first determine whether the physical keyboard is faulty by testing another keyboard.

1. Identify whether it is hardware or Windows

1. Open Notepad and test M, V, C, X, Z.
2. Open the on-screen keyboard:
   • Select Start, type On-Screen Keyboard, and open it.
   • Click those letters with the mouse.
3. Test with another keyboard:
   • Laptop: connect an external USB or Bluetooth keyboard.
   • External keyboard: connect it directly to another USB port, without a USB hub. If possible, test it on another PC.

Interpret the result:

• On-screen and replacement keyboards work: the original keyboard likely has a physical problem.
• The external keyboard fails on another PC too: replace or service that keyboard.
• Multiple physical keyboards fail only on this PC: continue with the Windows checks below.

Microsoft recommends testing another port or PC and replacing the keyboard when it also fails on the other computer.^1^

2. Clean the affected keys

Shut down the PC and disconnect the keyboard if possible. Check around M, V, C, X, and Z for dirt or lodged debris.

• Use short bursts of compressed air between the keys, or gently vacuum the surface with a dusting brush.
• Do not pour cleaning liquid into the keyboard or force off laptop keycaps.

Microsoft specifically recommends removing debris when individual keys do not respond.^2^

3. Check Windows settings and updates

If multiple keyboards show the problem only in Windows:

1. Go to Settings → Accessibility → Keyboard.
2. Temporarily turn Filter Keys and Sticky Keys off.
3. Go to Settings → Windows Update → Check for updates and install available updates.
4. Restart the PC and retest the exact keys in Notepad.

Accessibility keyboard settings can cause keystrokes to be ignored, while Windows Update can provide applicable keyboard drivers.^2^ ^1^

If updates do not help:

1. Right-click Start → Device Manager.
2. Expand Keyboards.
3. Double-click the keyboard.
4. Select Driver → Update Driver and follow the prompts.^1^

If an external keyboard works normally but the built-in laptop keys still do not work after cleaning, arrange hardware service with the laptop manufacturer. Individual keys that continue dropping input after debris is removed are consistent with a keyboard hardware failure.^2^

References

1. Mouse and keyboard problems in Windows | Microsoft Support
2. Troubleshoot Surface Pro Keyboard or Type Cover | Microsoft Support