I'm with Draco, the random nature sounds like something else is causing problems. I it had any sort of repeat pattern, I would think otherwise. I just had a paried set of Crucial DDR3 suddenly develop a failed stick, and while it wasn't obvious at first that's what it was, memtest sure found it in a hurry. Might want to let that run for an hour or so and see if it finds anything (the built in windows test is worthless IMO) <edit> it crashed all the time, but never the same way, sometimes immediatley, sometimes 5 minutes after reboot, next time 15. <edit 2> I went through this with my dads i5 build running onboard video, and it was bad mushkin memory in this case too. Seems the onboard video is particularly picky, and will show any weakness. His machined would run days if it was just idling, but put it to task with anything video related and it was crash and burn, with all sorts of strange anomalies! I'd go through the process though, and go grab the latest reference driver from Intel/AMD just to rule out driver issues. I think troubleshooting the memory is where I'd start after that exercise though.