New comp build Freezes every ten Minutes

So, I assembled a comp the other day, everything is working fine except for some reason every ten minutes it will freeze, then the next time i restart it will only take 6 minutes, then 3, then 1. I assumed it was a overheating problem because the cpu was running hot; however, it is still freezing even with a fatty copper "typhoon" heatsink and fan. Next i assumed it was simply my memory timing was off, since my memory timing is supposed to be 4-4-4-12, but it was running at 5-5-5-15. However, whenever I switch that in the setup, it causes my computer to criticly fail, unable to even boot up to a setup screen. I'm having so much trouble identifying the problem because for the ten minutes it is working, it is workign beautifuly: graphics are rocking, cpu is blazing, all are recognized by the computer and are working normal. The only thing that I have found as a possability is that it seems that the nVIDIA NF570-Sli heatsink deal on my motherboard gets REALLY hot. I dont know why it would do this, i have my XFX Geforce 7600GT plugged in and reading fine. So i assume this could be why it keep restarting, but if so, what can i do to stop it? Buy a fatty cooling system? Switch it off in the bios? As a side note, i tried flashing Bios 0203 on my comp, had trouble getting the disk drive to read it or something, anyhow, couldnt do it.

Thanks for all advice and help, i just wanna play BF2 =)

-MA