First Build Help - Freezing in BIOS

I am working on my first build and I have ran into a few problems along the way.

Originally I decided to build my system around the E6550 CPU and 680i Motherboard.
I bought an XFX 680i SLI motherboard and the E6550. My intentions were to build a budget system to run SLI. I also purchased 2 BFG Tech 8600GT OC 512mb video cards.
When building this system I could not get any kind of video out to my monitor. No BIOS or anything.
To troubleshoot I bought an E6750 thinking that the CPU could be bad. I replaced the E6550 and still no video.
I contacted XFX and got an RMA for the board.
In the meantime I bought an ASUS P5N32-E SLI to replace the XFX 680i.
I installed the E6750 into the ASUS board and was able to get into BIOS... for about 30 seconds. It then froze up and I wasn't able to do anything.
After a hard reset the BIOS screen loaded again and then it froze up before I could read or change anything.
I removed the CMOS battery and drained the capacitors to clear everything out. I reinstalled the CMOS battery and was able to get a boot into XP. I assumed the drivers for the mobo were loading and then it restarted on it's own. Again it rebooted and went to XP. It loaded very quickly this time then restarted. After this second time it rebooted and loaded XP then froze again.
After another hard reset it made it to the BIOS screen then froze again.
I replaced the E6750 with the E6550 and it worked for about 30 seconds again then froze.
All other components in my system have been confirmed in working systems.
If anyone has any ideas please let me know. It is becoming quite frustrating.
I apologize if this has already been covered in a previous thread.
Thanks



My setup
CPU: E6750, E6550 Core 2 Duo
MOBO: ASUS P5N32-E SLI (BIOS Version 1503)
RAM: OCZ SLI DDR2 800
HDD: Seagate Barracuda 500gb 7200rpm
GPU: BFG 8600GT OC 512mb
PSU: 750w