I'm running an HP p6620f desktop. Came home from work and found a black screen on my monitor. After checking the connections, I plugged the DVI cable into my laptop and the monitor worked fine. I assume my graphics card is shot. Purchased an inexpensive GeForce GT 610 video card, inserted into the PCI-E slot, and turned the computer back on. Still black screen on the monitor. Any suggestions? I'm wondering if I need to go into the BIOS or something to change the default? Kind of hard to do with no display. Thanks.