I think your 82 degree C is a little high. However most PCs are designed to turn off automatically if the CPU is too hot.
When was the last time you cleaned the dust from your PC? Dust acts as an insulator. The more dust the more heat is trapped.
Here is the C-Net link on how to do so.
Depending on the age of your computer and on how munch you use it, I think you should replace the thermal paste.
I posted eariler about not being able to get past boot screen and i couldnt find out what was causing this, after talking to a friend he said to check the temp of my cpu and gpu...so i downloaded speed fan to check the temp of my cpu and this is what i got...(AMD Phenom Triple Core 8450, ATI 4870 Graphics Card.)
GPU Temp: 43C
One of the temperatures is very hot compared with the others....could this have been causing my problem and if so should i just go and get a new CPU or try replacing the heatsink and putting new thermal paste on?....Let me know what you think.