I built my current computer about a year and a half ago. I'd tried to OC the CPU before, but it never took. I had a good grasp of things but assumed I was screwing something up and decided to leave it. Fast foward to a week ago. I tried overclocking the i7 again and had the same issues. Even on 3Ghz it would boot as far as the OS and restart itself.
I decided to check my temps and I found that I was idling at about 68c. I knew this was off, so I ran out and picked up some Arctic Silver 5 to re-mount. Upon removing Intel's stock cooler, I noticed that the thermal paste was splotchy and dried looking and there was dust on the CPU. I cleaned off the dust and old paste and laid down some AS5. After struggling with Intel's HSF a bit, it was re-mounted and I booted up. My temps were about 65c. I realized, however, that my temps were jumping up to 80-90c. The HSF had been wobbling partially off of the CPU.
So here I am, with my case on its side, letting gravity hold the HSF in place for me. My temps are now about 65c.
Does this sound like a cooling problem? I've been looking at buying a Spire TherMax Eclipse II.