The letter keys on my Lenovo keyboard have stopped working, while the number keys still function normally. Because I can't type letters, I'm unable to sign in. I've already tried connecting a USB keyboard, but it has the same problem. I'm not sure whether this is caused by a stuck key, a software issue, or hardware damage. Any troubleshooting ideas would be appreciated.
2 Answers
Since both the Lenovo keyboard and an external USB keyboard are affected, try opening the on-screen keyboard from the sign-in screen so you can enter your password. After signing in, check the keyboard layout and accessibility settings, including Filter Keys and Sticky Keys. If the letters still don’t work in BIOS/UEFI, it’s more likely a hardware or firmware problem than a Windows setting.
If the USB keyboard has exactly the same problem, the issue may not be with the built-in keyboard itself. Check whether a key is physically stuck, especially modifier keys like Fn, Ctrl, Alt, or Shift. A stuck modifier can change how other keys behave. Restart the laptop and, if possible, test the keyboard at the sign-in screen or in the BIOS/UEFI menu to help determine whether it’s a Windows software problem.

I tried another USB keyboard too, but it behaved the same way. I’ll check for stuck modifier keys and try the on-screen keyboard.