Ram bad? Unstable build!

Well this started off as just a few random reboots and it still doesn't interupt my daily use very much, but I decided to run some stability tests. Memtest 86 ran for 12 hours without an errors. Prime95, small fft's has run for almost 12 hours now without any errors. The Blend test somestimes locks my computer up within about 10 minutes, and large FFT's typcailly fail after about an hour and a half. Also sometimes when I start up 3dMark06, the system scanning tool at the beginning locks my entire computer up. I also got a IRQL Not less or Equal BSOD while running the Large FFT's test once.

I"ve tried messing with so much crap. I turned off cool and quiet. I've double and tripple checked my memory timings and voltages, and even tried relaxing my timings from 4-4-4-12 to 5-5-5-18. I know temperature isn't the issue. it barely peaks over 50 celsius under a full load. I have the Vcore set to 1.3 but every program is saying that it is actually running at 1.35, but I figure since the ideal range is 1.3-1.35 that should be fine anyways. I'm really at a loss here of what to do. I don't know if its a settings problem, a hardware problem, or what. My power supply seems more than adequate, I don't really think that is the problem either.

Can anyone please help me ?

Asus M2n-SLI Deluxe
amd 4200+ x2
Corsair 2 X 1024 XMS2 DDR2 800, CAS 4
Hiper 580 watt PSU

Sounds like a memory problem to me. I had a similar situation last year with random reboots, and despite the fact that Memtest86+ could run all day without errors, I eventually determined that one of my memory modules was bad. I discovered this by running the memory modules invidually and using Prime95 blend test. One of the modules could run for 20+ hours, while the other would fail after about 2 hours. I RMA'd the memory and everything worked fine once I got the new modules.

I agree with this. I'd try swapping out ram modules if possible and see what if anything changes.

Tried, both sticks failed the prime95 individually, either they are both dead or, more likely, the memory isn't the problem

I'm getting so stressed over this