@trailbeast 5help 5me 5out 5here

You press #5 and it acts like a spacebar. And you also get a "5" after you press the spacebar. Hmmm. It could be software or driver related, but I would first rule out the keyboard. Go borrow another keyboard and try it out. Is your keyboard wireless, wired USB, or what?

I also like trailbeast's idea of reinstalling the keyboard driver.