I have an ATI Radeon HD 4870 and an nVidia GeForce 8800GT that were originally used in my Mac Pro. I have another video card that is currently running in my 8 core 3,1 Mac Pro, so I am not using the other two graphics cards. I am trying to use them in a Windows based system I built. System Specs: ASRock P45DE3 Motherboard - PCI Express 2.0 x16 - PCI Express 1 (x3) - PCI (x2) Intel Core2Duo E7500 2.93GHz 775 socket processor Antec Three Hundred Mini Tower I know I have to flash either graphics card to work with the PCI Express 2.0 slot. I have installed each one separately without any video output (nothing comes up at all). I have the nVidia flash files (I haven't checked into the ATI Radeon HD 4870 yet), but I do not know what to do in order to boot the system with the card in order to flash it. I do have a GeForce 8400GS that works in the system, but I'd rather not spend the ~$60 for a card I do not need when I have perfectly working graphics cards. Do I need to have TWO graphics cards installed and running, the nVidia GeForce 8400 to boot and the other to flash? If that is the case I'll have to find another system as I only have one PCI Express 2.0 x16 slot to utilize. Any suggestions? What may I be doing wrong? THANKS!