Well you probably won’t like this but your assumptions are mostly wrong.
Ubuntu is a linux/unix/debian OS largely written by enthusiasts in their own image. Often minor changes in world wide payment systems will cause this sort of problem. Now your points:
a) No, the BIOS is merely the basic I/O system for the hardware, you will be using the OS features as installed. Nothing “goes on” within the hard drive beyond the storing and retrieval of data.
b) Correct, this is unlikely to be malware, but not because of not being able to “cope with” but because so few bother using these amateur operating systems so it’s not worth the effort.
In my opinion your problems are caused by subtle changes in the world wide payments systems that have not been propagated to your OS. I recommend installing Windows 7 (Not any later) and then using GWX to prevent MS from forcing W10 on you. I hope that helps, Buenchico is pretty good in these areas, he may well offer more advice.