I have a dell 875 watt psu, When I install the graphics driver my pc restarts right after the the welcome screen. Is it psu causing this problem? The card works fine in another pc, And I can run my pc in diagnostic mode but as soon as I run any program it crashes and restarts. I had a 5870 before and it worked fine, what should I do? I want to make sure its the psu before I buy one.