I just got a new HP computer with Windows 7 pro. When I install the graphics card, Nvida Geforce GT 620, the pc will not start. It appears that the pc freezes before loading Windows 7. The monitor stays black and does not show anything. When I remove the video card and restart Windows I get an error message saying that Windows did not start correctly. How do I correct this? I can not do anything in Windows 7 because the video card is not there for Windows to see. This video card worked fine running Windows XP 64 bit on the old pc.