We assembled the PC and then did a clean install. Immediately when clean-installing XP, we got a blue screen. We then took out one piece of the RAM and an old hard drive. Second time XP installed fine.
Motherboard, harddrive, GPU, RAM, case and PSU were all new.
Yesterday, when my RAM was still at 1.8V, my PC even rebooted when i was burning a CD.
I think it's no coincidence that the bluescreens went away when a upped my RAM voltage.