My pc works fine running videos or using the internet. However, after running a game for more than 15 minutes, the graphics completely stop, the monitor goes black and the sound keeps playing residual effects from the game. It is impossible to go back to the desktop without cold rebooting. I have tried cleaning out my pc to no avail, tried uninstalling/reinstalling drivers. I've been using uninstall, then driver sweeper, then reinstall, all within safe mode. No luck!