Installed new CPU, now system is unstable!!!!!

I have a really perplexing problem and would appreciate any advice that anyone might have.

I have been running a mildly overclocked A64 S939 system for 1+ years now and, other than a bad Antec PSU, everything has been running fine.

I recently upgraded my CPU to an A64 S939 3800+ (OEM), and shorty after that is when i began experiencing problems. The system told me that my 6800GS (load temps @ 70c) was not receiving enough power. Soon after that was when I first noticed that my machine would randomly freeze during big file transfers between my tower and an external drive Ipod. However, transfers between my two internal drives work fine. Then i started getting random freezes, crashes, and BSOD's. I replaced the PSU , but am still getting the freeze-ups (but no more GPU messages). Yesterday it took several hours for the system to crash. Today it took 30 seconds or so. Also, the BSOD errors are always different.

I have tried:
-replacing the PSU again with a better one
-clearing the CMOS/meticulously checking and adjusting BIOS settings
-running Prime95 for several hours using swapping DIMMS in diff. slots
-reinstalling windows multiple times with different driver versions
-removing the overclocking
-closely monitoring my temps and voltages (all normal, CPU 30-45 @ load)

Nothing has yielded any errors or given me any answers.

I am suspecting the motherboard. To my eye, none of the caps are bulging or leaking. is this a logical conclusion? is there anything that I should try first? Is it possible to get a "bad CPU" that gives intermittent problems?

Also, ABIT's website appears to be down, I can't connect to it. Anyone know anything about this? Both their main page and the RMA dept. "cannot be found." (all other sites work fine).

My specs:

AMD A64 S939 3800+
Abit AN8 Ultra MB Nforce4 Ultra (no NVidia firewall)
4x512 Corsair Valueram 3200 DDR
80GB WD SATA HDD
160GB Seagate SATA HDD
NEC $30 special DVD-R drive
Logitech G5 mouse
FSP 450-pn PSU


Thanks