I've just taken it off and attached it again, and now it's working all the time. I am getting a few CPU led's pop up on the mobo (x58a-ud3r mobo), indicating voltage above normal but they turn off after a few seconds. Could this be a BIOS configuration?
Also, previously when it turned it on and I had the case standing vertical, the cpu would make sort of a 'ticking' sound, but if I lay it flat it goes away. The heatsink seemed secure when i attempted to move it, so I'm a bit worried this will return.
Check to see if you have a wire touching the fan.. that is usually what the tick is. i have seen it a million times sometimes when oriented a certain way it just comes close enough to touch sometimes just barely