I was building a new PC last night, and I have stumbled upon a problem. I had everything hooked up, but the computer just wouldn't turn on. So the strange part was when I removed the 12V 4-pin connector from the mobo, it came on right away, but I wouldn't receive a video signal, it seems that the video card isn't even running (I can't really tell). Mouse and keyboard aren't on either. Anny idea what it might be?