sounds like you picked up a pest. I would run both As-Aware 6 and Spybot S&D 1.3 both with current updates. You can also try a online virus scanner like housecall.
I have a dell desktop that is running XP. My keyboard just starting to require you to hold down each character for about 2 seconds before you see it on the monitor. I tried to update my keyboard driver and reinstall it, with no success. Tried 2 new keyboards also, no luck. Must be something wrong with the computer. If you have any idea please let me know. Thank you.