So with one tap of "I" it sometimes types "II", yes?
This is called "chattering" and is usually only fixable by replacing the switch. There is a program you can use to test for chattering, though I seem to have forgotten its name.
Soldering in a new switch is fairly easy. I've done it myself, and I didn't break anything. If you're worried about breaking something, there are plenty of users you could send your board to to have fixed.
Find that program now that you know what the issue is, test your board, and proceed from there.
Seriously, Test if before you take it apart.