CNTRL Disabled??? Now I'm Lost

I have recently come up with a problem and it is totally baffling me. After a recent windows update (before sp2) I have started having problems with the control key. It is almost like the key has been disabled. when pressed to do a common keyboard shortcut like copy this is what happens c and that is it.

currently I am running Windows XP (with the recent sp2 update which has not helped), I have avast antivirus running (and it is set to automatically update), I have run ad-aware, and have tried the cleaner. Avast recently found a trojan on a deep cleaning.

My son sometimes uses the computer (YTV.com and like sites) so I am not sure how I was infected with something. Any ideas would greatly be appreciated sine I work in graphics programs frequently and it is a lot easier with keyboard shortcuts.

Any help would be greatly appreciated.