You'll probably want to go and ask for help in the Mining section... those guys have a lot of knowledge with regards to hardware setup and troubleshooting. Given that you're playing with GPUs, I'd suggest the "Altcoin Mining" section:
https://bitcointalk.org/index.php?board=160.0Start a thread there (or move this one)... and then update your post with all the relevant details regarding: CPU/Mobo/RAM/GPU types/PSU/Riser cards etc