My laptop makes a beep whenever I press 'C' and 'E' in quick succession while holding SHIFT. What is going on?

Solution 1:

For more troubleshooting, have you tried it on a separate attached keyboard? Perhaps one with high key rollover? If a separate keyboard does work, then there's a chance it's a hardware problem with your laptop's keyboard. Diagram of keyboard circuits. You mentioned checking all key combinations, but that's 36 choose 2 = 630 combinations when only using the alphanumeric keys, so maybe you missed some. E and C are on the same column, so make sure to try E+3, C+3, or E+D or etc., as well. If these combinations beep, and a separate keyboard does not beep, there's a good chance it's a hardware problem.

Moreover, if this is Windows 10, there are more options than just disabling Sticky Keys; also check Filter Keys and Toggle Keys.

Lastly, have you updated your BIOS to its most recent version?:

https://support.lenovo.com/us/en/downloads/ds502400]1

Ironically, if that doesn't work, I'd also suggest trying rolling back your BIOS to a previous version before the issue started, if it's a recent development. I'd only recommend rolling back if this problem is especially bothersome.