XP freezes solid……………………….

if I leave my pc (2.6P4, 1GB RAM, 40GB drive) for any length of time it freezes up solid !!!!!

I was under the impression xp wasn’t meant to do this. the keyboard locks up completely too.

I have changed video cards, and put on a different mouse and keyboard, but no change.

does anyone know if this sounds like bad memory, and if so, how do you determine which card, trial and error?