You won't get anywhere without actually looking at your voltages, what is CPU-Z showing as your CPU voltage when it's under load?
Also, take a pic of the inside of your PC, showing the layout of your cooler and fans etc. Often with cooling problems like this there's just some issue you might have missed that we might spot for you
Just kidding... Here are a few:
A note about the heatsink: Yes I realize it's blowing up, I did this because when it's facing the other way it is lightly touching my northbridge so I thought I would try it facing up and see if perhaps the light touch was off balancing it. I should note that it was not, and it made no difference either way.
Edit: I realize one of them was a duplicate, fixed.
Edited by kshawkeye - 5/21/11 at 4:09pm