Basically when I got home this afternoon, I went to turn on my computer. I heard the sound of windows, but I was only getting a black screen. I restarted, and this time, no windows loading sound but still the same black screen.
I figure it's the GPU, so I replace it with my old one, but no dice. I try with 2 other GPUs, but still the same black screen. I try my old PSU, but again the same problem. So now I take everything out, and put it back together, interchanging EVERY single part with spare stuff that I know works. Nothing changes. Same black screen upon startup (even though it POSTS). I do know there is a signal there, because my monitor flashes up if theres no signal. In this case it's just displaying a black screen.
Then I randomly try a spare $30 video card and lo and behold, it boots fine. So I try putting in the original video card, but now it doesn't boot. In fact none of the higher end cards boot. The only thing they have in common is that they all need supplied power.
So, can anyone tell me why my computer will boot with a tiny little GPU that uses no extra power cable, but all my other ones result in this black screen? I've tried literally everything and nothing so far has helped.