Computer Tech Help

[reo]

Got this machine that I used to never have any problems with. I would have it running 24/7. Suddenly, about a month ago, the machine would shut itself down after an hour of use.

So what did I do? I checked to see if all fans were running but that wasn't the issue. After doing that, I checked to see if it were some settings. I haven't cleaned the machine in awhile so I decided to just do a format and get to a clean state since I wasn't sure if I had tinkered with some setting beforehand.

By the way, when I say shut down, the machine itself doesn't just turn off. The discs continue to run but Windows isn't in hibernation / standby mode. I have to manually turn it off. I decided to just check temps in BIOS but nothing is out of the ordinary. I also checked to see if it was some power management issue but I have everything set to "never" because I use this machine to store movies, games, etc. I also don't have hibernation mode enabled.

At this point, I don't know what else to do. If you have any ideas, please let me know. Thank you for your time.