I'm not 100% on why my keyboard randomly stopped working.
Things I have done recently:
1. Installed SP3 (Seemed to cause no issues for about 3 weeks.)
2. Installed Synaptics pointing device driver (can't stand tap-click.)
3. Keyboard worked fine for about a week then...
3. Found keyboard became completely unresponsive in XP.
4. Uninstalled Synaptics pointing device driver (see if keyboard would work again.)
5. Keyboard still not working so checked in BIOS.
6. Keyboard moved around and could de/select items just fine.
Any help with this one greatly appreciated, but if all else fails I'll probably just have to reinstall. D'oh!