Pc shutsdown unexpectedly

Yesterday my PC shutdown unexpectedly and when I tried to restart the system it would start to power up for a about 5 seconds then shutdown again, i then tried to start it again with the same result. Toady when it started the system it fired up and ran for about 15 minutes then shutdown again, when I tried to restart it would shutdown after 5 seconds. I let the system set for 15-20 minutes and restarted the system, it ran properly so I think it maybe an overheating issue. While it was running I downloaded CoreTemp software and it showed core 0 at 100 deg C, core 1 at 100 deg C, core 2 at 100 deg C, core 3 at 100 deg C, and when i installed the Core Temp software core 0 and core 1 were at 100 deg C then core 2 moved to 100 deg C and shortly core 3 moved from 98 deg C to 100 deg C. I built this system and installed it in a Thermaltake case that is very well cooled as is the I-7 chip. Is this a warning of future chipset failure or motherboard failure? Any ideas what happened?

Just to clarify, when was the system built? has it been working fine since then? or is this a fresh build, that is overheating?

Maybe the cooler isn't making a proper contact with the processor? sounds most like it, due to how fast and badly it heats up.

checked the fan on the CPU and one of the mother board cables was touching the fan blade preventing it from turning, put a velcro tie on it, now the fan works fine and should take care of the overheating of the CPU. Will run the system for an hour or so to make sure that this solved the issue. Will report that its solved in an hour or so, also this system was built in 2010 and never had this issue before yesterday as I was moving the tower case to add a usb printer cable and that may have caused the cable to move and block the CPU fan blade...Thanks guys for your Help

The issue was a cable was touching the fan blade, once it was secured away from the blade the PC worked fine. Thanks again for your help

Thanks so much for letting us know,
I don't exactly think you needed help - seems like you've done the troubleshooting and figured out the cause on your own. Still, I very much appreciate you sharing your experience with us - I wouldn't have thought that simply moving a PC could dislocate a cable and block the fan so easily. Glad to hear it was as simple at that :)

Actually the issue with the cable was only discovered after one of the members mentioned the fan, it was then that I checked to see if the fan was running...so yes this forum really helped with the issue...windows 7 forum rocks