If all else fails, a reinstall would be best at this point. If it still does it after ward, then you will at least know that it's not viruses or settings and possibly hardware related.
I'm not sure how often you look inside, but have you seen any blown capacitors on your motherboard or video card?
i7 3930K @ 4.2 Ghz | Asus Rampage IV Extreme | Asus GTX TITAN TRI-SLI | 16GB G.Skill Ripjaws Z DDR3-1866 | Corsair H100i | Corsair Force GT 90 GB SSD | 2x Corsair Force GT 240 GB SSD | 450GB VelociRaptor | Sound Blaster Z | Corsair AX1200i PSU | Logitech G500 | Logitech G110| CM HAF-932 Black Edition | Asus VS248H-P | Win7 Ultimate 64-bit
Lenovo Z575 - A6-3400 | 8GB Kingston HyperX DDR3 | Kingston HyperX 240GB SSD