Jason wrote:

I just wish that MS could have at least told me if the failure was
something software-related or a hardware incompatibility; the machine is
rather old.

You can always save a backup image of the OS partition(s), do a fresh
install of the OS and drivers (but NO APPS, not even anti-virus), to
test if the problem remains or went away. Then you can decide if that
long-time refined setup is worth retaining or reinstall the apps, do the
tweaks, restore the data, and go forward with a non-polluted instance of
the OS. Or start saving for a new computer so your old one remains
usable until you decide to switch to the new one.