I have an Asus (K52Jr) laptop for almost 4 years now. I'm working from home for almost 3 years so I use the laptop extensively.
I never had a problem with the keyboard, but, suddenly yesterday it started skipping random letters. It seems improbable for me to be because of dust or something like that because it wasn't a process in which letter by letter the keys stopped working, instead it affects all the keys all of the sudden. For about 2 hours last night it worked well again, but this morning started acting strange again.
So, today I removed my keyboard and cleaned it thoroughly. It didn't help. It still skips letters. And I noticed something else today, also. If I keep a key pressed from time to time, while repeating the key, it stops a little, like I would lift my finger up and push the key again.
I can't understand what's going on. Could it be something with the data cable? When I cleaned the keyboard today I plugged out the data cable also (in case something wasn't plugged in correctly).
I also booted in Safe Mode, to see if it's a software problem, but the same issue occurred in safe mode also (even in the "Repair mode with command prompt")