Listen, I checked out Task Manager and Resource Monitor, and I can easily see that the CPU usage maxes out at 12% and never goes over that limit except after a cold boot, and then only for a few minutes. I thought it was definitely some internal hardware throttling due to a thermal issue, but then it would have to affect the Linux OS as well, wouldn't it?

That does sound strange. Might be some weird laptop/driver shit. My desktop is built and the only Windows laptop I use is a corperate one with a custom Windows image from IT. But Windows "walmart" style laptops for home use have always been kinda sus due to all the bloatware on them.

Might have needed a clean Windows reinstall.

Or maybe I'd install Windows again and find it does the same thing it does before.

shrug I'd love to say it's working well for her, but we haven't really gone all the way down this road, I know it will work to use Linux, but it still sits on the shelf and she's still dealing with Windows, (on the more expensive slightly older laptop which also has problems.)