Question Weirdest computer-related problem I've ever seen : 'A' button doesn't work when battery is low


Jul 17, 2018
Yep, as freakish as the title says.
My laptop (a late-2015 Lenovo IP700, Skylake-era laptop) has been showing a very weird behaviour. I don't know why or how, but when the battery is low (about 20% and below), the A button (the letter) on the keyboard stops functioning completely. It just doesn't register whenever I press it. This includes typing in Microsoft Word (or any other text input) and using it as key combination (Ctrl+A, for example). Other keys work fine, including keys adjacent to the A button (the W,S,D, Caps Lock, etc.). The problem also goes away if I plug it in, or if the battery is anywhere above 20% mark.

I first noticed it when one night I forgot to plug in my laptop and it went to sleep. When I turned it on, the battery almost ran out (around 9%-ish). I had something that I needed to do urgently so I typed in my login password and it kept saying 'wrong password' despite I supposedly typed it correctly. It dawned on me the laptop didn't register the A key. The laptop shuts down (battery died), I plugged in, and I could log in first try no problem. It took me a few days to realise what was going on.

I haven't tried much, just antivirus scan and a system restore. The problem seem to materialise after the latest Windows Update (the one that introduced the weather on the taskbar). Nothing I've done has resolved the issue. It's not really a problem though, as my laptop rarely goes too far from a power outlet, but still.

Any idea on how this could happen? And no, I couldn't make the connection either between battery running out and part of the keyboard not working.