Hi all, I just got a new gfx card, the xfx 6870. I put the card in, fit perfectly in my motherboard but when i started up the pc, my moniter got a blackscreen and just sat there. I would of thought it was a problem with my power supply, but the motherboard gave me the same short beep on startup which I thought meant everything is okay. I can hear it making welcome noises through the headset. It just seems like the video isn't there. Also, when i turn the monitor on without anything attached to the cable on it, it says "check signal cable", but now, it is just a black screen. Please help...