Control Button on Keyboard won't work!?

I keep trying to use the CTRL (control button) on my keyboard..both sides and it won't work. I've tried different keyboards, made sure non of my programs, sticky keys, anything like that could be interfearing with it. I'm on XPSP2S..I heard there might be some problems with it that way...I can't even do CTRL+ALT Delete..I've used keyboard diagnostic programs, and they didn't even register the control key being pushed on multiple keyboards, it's as if my computers blocked it! Is there any advice anyone has? I would greatly appreciate it!Control Button on Keyboard won't work!?
..i really don't know what to do..because i didn't experience a problem like that...but do you already restart your computer?..if you already restart and it won't help..try to reformat..it is just my opinion..