Recently i won PowerColor PCS+ HD7870 2GB GDDR5 (Vortex II Edition) from TPU-GPUZ competition and when i ran bf3 and all the latest game slike max payne 3,ghost recon future soldier the game hangs after some time and and screen goes black and system gets stuck and i've to restart using the reset button as nothing works...donno why this happens.my latest driver version is amd catalyst 12.6.power supply is o.k but it is not running games... . please..........Help!.