Install the latest driver for your GPU. Post here your PC configuration, maybe I can help you more. Microsoft Windows 7 Ultimate 64-bit Intel Core i7 2600K @ 3.40GHz 8,00GB Dubble-Channel DDR3 @ 414MHz MSI P67A-GD55 (MS-7681) 1536MB GeForce GTX 580 (nVidia) 932GB SAMSUNG HD103SJ ATA Device (SATA) 1...