I'm having some issues with my 2011 model iMac this morning. I was playing a game in Windows under bootcamp. All of a sudden the screen went all funky. It was filled with lots of wavy lines and then it went blank. I had recently reinstalled bootcamp drivers and I thought this might be an issue. I rebooted and then reinstalled the latest AMD Bootcamp drivers. I loaded the game and then got to its menu. When starting the screen went blank and the machine hung. -I tried rebooting into Windows but it got as far as the login page before going blank and rebooting. I tried to reboot again and it got as far as the Windows logo but rebooted at this stage. -I decided to boot into OSX to see if this was just an issue with Windows. I got as far as the progress bar. This went about 70% along before a reboot. I tried to reset the PRAM and SMC without this resolving things. -I tried to boot into recovery. This again showed the progress bar before rebooting at around 70%. -I tried to run the AHT. This wouldn't load so I loaded it from the net. I ran the short test and it found no faults. It is currently running the extended test as we speak. If this shows no faults, what should I do? As an aside, I have the AMD 6970M in this machine which Apple has a replacement programme for. Is this likely to be the culprit?