I have a co-worker that is reporting an odd issue. From a cold boot he is logging into windows and after about 2 minutes the screen goes black. The computer is still running in the background only the screen is black. Once he reboots the issue never reoccurs until he restarts the computer from a cold boot. I mentioned possible driver issues and he has updated. He is running Windows 7 and it is a desktop with an NVidia card.