Hi Guys, last night i was trying to render a video and for some reason everything froze up and my computer restarted! And today when I was watching some videos online, the exact same thing happened again! Now I'm not sure if its a drive issue or a hardware issue. Does anyone have any idea? My graphics card is the ATI HD 6950 2GB, running the ubuntu's drivers. I only purchased it back in July so its still in warranty if its a hardware issue.

Many thanks, and if anyone has any suggestions I would be grateful.