Try reposting this in the 'Q&A' forum. The 'Discussion' forum is for matters of general discussion, not specific problems in search of a solution. The 'Water Cooler' is for non-technical discussions. You can submit a question to 'Q&A' here:
https://www.techrepublic.com/forum/questions/post?tag=mantle_skin;content
There are TR members who specifically seek out problems in need of a solution. Although there is some overlap between the forums, you'll find more of those members in 'Q&A' than in 'Discussions' or 'Water Cooler'.
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[b]It's likely to be heat related[/b] so look at the CPU Heatsink. It's likely to be full of airborne crud and is stopping it shedding heat. Also check the CPU Fan for correct Function and then Look in the BIOS at what Temp it Auto Shuts Down to prevent Damage. If it's below somewhere around 85C reset this to 85C and remember to save the changes as you exit the BIOS.
If it's not that and this is a Desktop I would be looking at the Power Supply as the Possible Culprit.
Col ;)