Control Key Lockup

Windows XP desktop. Control key will stick every so often and anything I do will interact with the desktop as if the control key was depressed. If I click on an icon, it selects it, just as if I was ctl+clicking. I’ve looked at the accessibility options and as far as I can tell sticky keys is disabled. I’ve tried a new keyboard, reinstalled the keyboard driver. I can’t see any way to tell XP to simply “uninstall” the accesibilty options.

It isn’t an all the time problem, if I reboot the issue will go away for a day or two, then it will pop back up. I don’t think the user is accidentally holding down the CTL key, when I asked him if he was resting his hand on the corner of the keyboard he told me he was very careful to avoid it after ourfirst discussion on the matter.

So, I’m turning to others for suggestions.
Thanks. -Todd