pop off the spacebar and press the rubber nipple down to see if it will make the space bar create a SAPCE on the screen. if it doesnt, then buy a new one for 10 bucks at your retail store. If it does werk, then snap the space bar back on. Also try attaching another KeyBoard to the mahine, reboot and see what happens.
future reference, invest in AntiVirus.
i hope this helps.
/CLONE