Yep got same problems without OC. Id think the PSu is alright though since i already killed one so this is the second. I think (hopefully) the problem of completly restarting is gone, i had to mannually install the video drivers in VGA safe mode.
Make sure you turn off your anti-virus! Make sure you disable any Zone Alarm programs you might have running. If try to install graphics drivers with anti-virus running (not scanning, just in the system tray) it will not let it install correctly.