Nvidia Geforce 7900 GS 256MB VGC video card not detected

I purchased a repaired NVidia GeForce 7900 GS 256MB VGC (Video Graphics Card) PCI-Ex16, having a PCI-Express x16 slot. I also purchased a power converted. After connecting it, my PC did not detect it. Thus, I searched for the drivers online and installed them, but the error message says that my Video Graphics Card cannot be detected. In brief, my PC is not detecting my VGC although it is has been properly inserted. Do you have any solutions to this problem?
