Help, is my problem my PSU?

[ddarksiderr]

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?

 

[lunyone]

Well my first thought is the PSU has an issue, but don't know for sure. If you go back to a single GPU, does the computer work fine?? If it does, than what I'd try is put the other GPU into the system by itself and see if it causes any issues. This way you can rule out the GPU's individually.