I am about 99% sure your problem is the heatsink mounting. You are not supposed to mount it while the motherboard is in the case.(Majority of people do this and end up only having 2-3 of the pins properly pushed in) They also end up making threads like this and this ends up being the problem almost every time. The reason your machine finally crashed is most likely another pin came loose and contact with the processor was so poor that it overheated.
Take your motherboard out, and put the heatsink on again. Look behind the motherboard to ensure that all four push pins are sticking out all the way. Be very careful when you put the motherboard back into the case, do not touch the heatsink. Also be careful of putting memory in because sometimes people bend the motherboard a little bit when they do this and it can cause the processor heatsink to come loose.
I run a Q9550 at 3.4Ghz with an Arctic Cooler Freezer 7 and I idle in the high 30s.
Take your motherboard out, and put the heatsink on again. Look behind the motherboard to ensure that all four push pins are sticking out all the way. Be very careful when you put the motherboard back into the case, do not touch the heatsink. Also be careful of putting memory in because sometimes people bend the motherboard a little bit when they do this and it can cause the processor heatsink to come loose.
I run a Q9550 at 3.4Ghz with an Arctic Cooler Freezer 7 and I idle in the high 30s.
