I have recently purchase a new system ( 2 weeks back). All hardware is brand new except for the graphics card. The hardware specs are: OS: Win 7 64 bit Service Pack 1 PSU: GX-650 watt RAM: 8 GB DDR3 Kingston Single stick Processor: Intel Core i5 4670k 4th generation 3.4 ghz Graphics: Nvidia XFX Gts 250 512 mb Motherboard: Intel DB85FL Hard Drive: Seagate 1 T.B Ok, Now the problem is that whenever I play any video game (such as GTA IV, Devil may Cry DMC, Metro: Last Light), my computer screen just freezes after 5 to 10 minutes of gameplay. My keyboard and mouse stops working and the sound just stops. Only way to get out of this freeze is to restart the system manually. Recently I put out my graphics card from the motherboard and played the above mentioned games with intel hd graphics 4600 (Built-in) and no freeze occur whatsoever and I played for hours. But my gpu never had any of these problems when it was installed in my old system and games works just fine. Need to mention that my gpu is PCI-E 2.0 and my motherboard supports a PCI-E 3.0 graphics card. I have read many forums that motherboards have backward compatibility and can run 2.0 cards as well. Also used windows memory diagnostic tool and it did'nt find any problems with the ram.I have also stressed the graphics card using Furmark but my gpu temp. reaches to abotu 100"C and I stopped the test. Please help me out here because I dont want to purchase a new card and I am just curious that it might be possible that the PCI-E slot is busted.