>How many buttons does your mouse have? Test different clicks and sequences and see if one of them pops it up...
It is something that is related to the keyboard. It is in the area of the QWERTY sequence.
>Also, some canon camera drivers in Windows 7 (non windows 7 drivers actually) have caused this in the past...
I have a CANOSCAN scanner. I do not know if that could be a factor.