Won't boot up with GPU in.

I have a Biostar TForce TF82000 A2+ RT mobo with a 8800GT, AMD 5600+, Rosewill RP500-2 500W PSU, and Corsair 6400 R 2 GB of RAM, and was working fine last night. This morning, however, the mobo did not boot up; the fans and LEDs (except for the HDD status and power button ones) turned on but the BIOS screen would not pop up and the GPU's fan would remain at 100%. I thought it would be a problem with the mobo, but once I removed the GPU, the computer would boot normally, so I figured it was a problem with the GPU.

After looking online, however, a lot of the results ended up with a mobo problem, so I'm asking for help in which hardware piece is causing the problems before I spend 150 on a new GPU only to find out it doesn't work. Can anyone help?

Have you tried testing the RAM? I had a stick go bad and all the lights and fans would turn on but it would not post. Might be worth checking if you have more than two sticks you can see if one went bad.

Good luck

Both sticks work and are at default settings, so RAM is not the issue. Thanks for the suggestion though.

I tried that but the computer will not boot up; the card stays at 100% fan speed as it occurs when it first starts up.

I vote bad PSU.