I recently tried to install a USB 3.0 card. When I did the screen went black. I took the card out and rebooted, the computer turned on , barely, the fan would just turn, stop and start again. A week or so ago I installed a MCI video card, I disconnected it , no change I then started disconnecting wires to see if it would change. I unhooked a wire on the top of the board, that was connected to a 4 pin male connection, this started the computer, at least the fan went back to normal and sounded like a good reboot. The problem now is I have no video, even when I rehook the video card.If I put the wire that I disconnected back it stalls the computer again. Wierd. Any ideas? T.I.A.