it would be nice to know what your mobo is too. But i would start over as well. Reapplly the hsf and reset bios. Increase the cpu frequency by 5mhz inquirements and boot into windows and run TWO instances of xtremesystem's version of super pi and then run orthos for about 2min. If it is stable, increase the teh frequency agian. When it becomes unstable, increase the vcore. If your on stock cooling, i wouldn't go any higher then 1.4 vcore. Im on a zalman with artic silver 5 and i keep myn at 1.35vcore cause my load temps sometimes hit 50'C, but i think thats cause i just wasn't lucky.
heres links to the stress testers: superpi
and i just remembered a great guide on stress testing: here ya go stress test guide