PC suddenly slowed down over the weekend, overnight. CPU will not go above .4ghz no matter what I throw at it

Hello everyone. I've had my Aurora R13 for 1.5 years now and been very happy with it overall. However, as of this past weekend, my system slowed to a crawl, with basically no load in task manager or performance monitor. After doing a fair amount of troubleshooting and making very little progress, I decided to reformat the PC.

After reformatting, the issue persisted. At that point I assumed it was hardware related, but I can't shake the feeling that this is somehow software/firmware driven. No matter what I do, the CPU will not increase clock speeds to accommodate for additional load, and it stays at exactly .4 Ghz no matter what. I even went into AWCC and changed the clock speed/voltage and in the test it just sits at .4Ghz. I'm past warranty, and really don't want to buy a new CPU without knowing that's the issue, so I'm exploring all avenues possible.

I tried running a CPU stress test, load never went above 12%, and the CPU stayed at .38ghz the whole time.

Any help you all can provide would be amazing, thank you!