Q6600 extreme temps please help

i was having some problems with my computer starting about 2 weeks ago or so. it started turning off at random times and i was confused because i thought it was either the motherboard or the powersupply. it would get to vista and just turn off and a friend of mine had that problem and it was a blown motherboard. well i took everything out and put it back in one by one to see if it was powersupply first and after i had everything back in it worked fine. well this week, about a week and a half with no problems it started turning off again well my friend said to check the temps through the bios. i just first turned it on and it was at 89c i was like no friggen way i mean it was overclocked to 2.7 but as soon as i saw that i set it to stock speeds and let it alone for about half an hour. turned it back on same thing. tried nvidia's system moniter and it showed same heat. tried 3 times to dl coretemp but it jsut turned off from i assume running to hot. im giong to try to reseat the cpu with some artic silver and a new cpu cooler insteed of stock cooler and stock thermal paste stuff. any other suggestions on turning down the heat because id really rather like to not melt my cpu. thats a bit of an exageration but i still dont want to damage it if it hasnt been already, which im really hoping it hasnt been because then i will be very sad.

As NMDante said make sure that the heat sink is seated properly. I had the same problem today with the same processor, I'd enter the BIOS and check the temp. It was at 95C then it shut down. Take off the heat sink, apply a thin layer of thermal grease and put the heat sink back on securely. This fixed the problem for me, now it idles at 30-35C and works fine.