Help, is my problem my PSU?

Recently I built a computer featuring a q9550, 2 1gb 4870s a p5e deluxe x48, and a zalman 850 watt PSU.

After enabling crossfire, the system began to display a bar at the bottom of the 28 inch monitor it was hooked up to. To fix this I tried to go into the catalyst control center which then said that I had no ATI graphics display driver or that it was not functioning, but it had worked before and I did have the latest drivers. I reinstalled it, but it still was saying that. I powered down the system and tried reseating the GPUS. It still did not work but then I developed a new problem. The system would not start. I would hit the power button and the fans would spin and the power light would go on and then die in several seconds and then did it again. I examined the PSU and discovered that I could hit the power button and get a response even when I had the switch on the off or on position. Is the PSU the root of my problems?

The machine was working great until this morning, when I tried to go into catalyst and then while trying to fix the graphics issues. What should I do?