Offhand, it sounds as if something's gone screwy in one of the hidden configuration files in your home directory, since the other user works.
I have no idea which file it could be. I can think of two things I would do to troubleshoot this in the absence of any additional enlightenment:
- Try another keyboard if I had one, because it's an easy and fast test, although I must admit that, in this case, it probably won't do anything but confirm that this is a software problem.
- Rename the hidden files one at a time to something like dot-hiddenfilename-dot-old, log in and test. Repeat until the culprit is identified.
Hopefully, someone who knows which file(s) are the likely culprits will come along and suggest something less shot-gun like.
Gratuitous rant: This is why I like booting to a terminal. If the GUI acts up, troubleshooting it ever so much easier when you can log out to the terminal, try something, and log back in to the GUI.