I've had my Q6600 for a little over a year now, I do no overclock and am running the stock cooler and stock voltage. Just this week my computer shut off instantly twice, one second I am gaming (RE5 once then Dead Space next) and the next second the computer is completely shut off. This has never happened to me before so I am a bit concerned. When I started it back up again I entered the bios to check my CPU temp and it was at 61c and I see that there is a setting for critical temp that was set to 65c. I don't want to fry my cpu and its weird because I have gamed on this with no problem for the last year. I ran Realtemp while I was playing Dead Space to see what temps I got and it ran up to 66 and I stopped just in case it shut down again. If it is really the temperature safety shutdown why hasn't this happened before? Does a cpu run hotter as it gets older or does the stock paste not hold up well over time? Its bad because its winter time now and I can only image what it will be like come summer.
It is possible your cooler might not be doing the job as well as it should. It might do you some good to thoroughly clean the fans on the heatsink of any dust on there. If you really want to go to town then remove the heatsink, clean it and reapply a fresh batch of thermal paste (arctic silver 5 or arctic cooling MX-2) and reseat the heatsink on the CPU. Either that or get a third party heatsink altogether for better cooling. I'm not well versed in how hot the C2Q's run idly etc but 60 degrees seems awfully hot (my core I5 never goes past 45 on 100% load in prime 95) so perhaps there has always been a contact issue with your heatsink and its taken it til now to manifest itself.
so I opened up my computer and took a peak inside to find the cpu fan and heatsink covered in dust (not surprising) so I took a toothpick and started slowly picking at and out as much as I could. So after a half an hour I ended up with a pile large enough to knit a sweater with! But, the best thing is now at peak my CPU runs 20c cooler! I saw after a session before the clean I ran up to 70c! now I'm running at 50c! awesome! thanks