Keyboard causes crash

Keyboard works fine in bios and other pc’s. However on this particular XP machine as soon as it gets into windows all the lights on the keyboard flash and then go off. As soon as any key is pressed the machine freezes up.
The mouse works fine. No keyboard entry in Device Manager. Nothing noticably wrong in Event Viewer.

Any ideas?

Apparently graphics drivers were rolled back before the problem started occuring. Could this have caused the problem?