I've reached the end of my personal resourcefulness on this one. The C655D-S5130 is a very basic machine with an AMD E-240 APU and AMD Radeon HD 6310 graphics. It originally came equipped with Windows 7 and "fell victim" to an upgrade to Windows 10 during the brief "hitting the red X dismissed GWX with implicit consent" period.
It had been essentially non-functional since. I decided to see if I could revive this machine if possible and found that it was still pre-anniversary update, CPU usage was typically in the very high 90s to 100%, and the processes hogging the CPU were the Antimalware Service Executable (which I didn't cure with the techniques I found) and one related to Windows Update (Windows Module Installer Worker) that I did cure.
SFC came out entirely clean. I decided to force an Anniversary Update, which did apply just fine, but the behavior noted in the subject did not resolve. I have since done a full Reset with the "keep my files" option, which removed a lot of applications, but the freeze-thaw cycles remain.
The AMD autodetect utility cannot find a suitable driver for this hardware.
CPU usage remains very near 100% at virtually all times, even when the system is responsive. The things that are "the hog or hogs" varies. Right now it's back to Windows Module Installer Worker, which keeps jumping to between 40% and 85%. Other times it's back to the Antimalware Service Executable while at other times it can be Windows Explorer, Task Manager, or some random other process taking 30% or more of CPU at a given moment.
I'm pretty much ready to declare this machine dead, but thought I'd ask here to see if anyone has experienced this sort of thing either on this hardware or other hardware that had some sort of simple solution. If there's something I can or should try please let me know. This challenge is not worth the effort other than as a learning experience as the machine was ultra-low-end to begin with (and I'm doing this for a family member, not a client).