I replaced my CMOS battery, changed all the BIOS settings back to the way they were, got into XP and found that certain keys on my PS/2 keyboard were not working (in this case, 'c', 'm', and Enter). Restarted the computer and everything was working fine for about 2 hours. Suddenly, the keyboard stopped responding at all. I restarted the computer but the keyboard is still not responding. No device is listed under Control Panel, Keyboard, Hardware. I doubt the keyboard is broken. I think it has something to do with the CMOS battery replacement. Any help would be much appreciated,

The first step is to always try a different keyboard.

Well like he said try to replace the key board. If that didn't work try using an USB type key board. Then if you are in the windows Desktop start scanning thee must be spyware Want A Weekly Update on Latest System Security Problem http://www.systemsecurityinstitute.org

Update: Restarted the computer and the keyboard is listed under Control Panel, Keyboard, Hardware now. However, when I type, no text appears and the computer hangs a bit. I am working on trying this keyboard out with another computer and trying another keyboard on this one.