If you remove the video card and the system runs fine on integrated, but you install the video card and the video card doesnt function it could be video card or power supply is running weaker than it use to. If its the power supply you will have no display out either nVidia video card adapter or integrated and system may run fans etc, but will probably not boot further. If its video card you can have no output from nVidia adapter, but yet integrated will run. If you have a spare video card that would be a good test device to swap video cards, install drivers, and see if that helps. If you install another video card and also black screen no display on either integrated or the video card then power supply is prob bad if it runs fine without video card installed and on integrated only.