I just rebooted into windows, performed a virus scan and left it going. Came back to find a blank screen. Nothing. Pressed the power button to restart. Fans fired up, the start up beep etc. Nothing. Eventually just left it going and went to my other mac and was able to log in via screen sharing. It appears to not recognise the graphics card anymore. Basic screen resolutions and going to the graphics/display section of the system profiler results in a crash. I bought this mac pro with the Ati x1900 which suffered from the over heating issues, so I replaced it with the nVidia 8800 which is the one that now appears to have broken. What's going on? This seems really very bad to have 2 cards break in 3 years.