I had the exact same problem with my computer when I built it. This power supply isnt modular, so I had a bunch of extra wires laying inside this damn thing. Anyways, comes to find out that the 8 pin (2x4 pin connector) power connectors near the north bridge werent plugged in all the way because the seats didnt match the board or the cables. So to fix that, I had to push those cables in nice and tight. Honestly, it sounds like you might even have a ground somewhere. What I would do is take the mobo out of the case, along with the psu. Put the mobo on its static bag, plug the psu up, mount the vga and monitor, and ground the power jumpers and turn it on outside the case. If you get the same thing, you just eliminated the ground, and/or a possibly defective case (and Ive had a few of those too).