I'll try and answer the first question about LibreBoot. LibreBoot is a BIOS
that does not normally ship on IBM/Lenovo laptops, but you can get such
laptops refurbished with this BIOS software. If you don't know what LibreBoot
is then it's almost certain you don't have it. What this means is that you
have a BIOS from Lenovo and it uses a whitelist. This means you can't replace
the internal card as only the card(s) in the whitelist will work. Generally
that would consist of the cards that the laptop shipped with. That would be
why you were told to go with a USB wifi adapter instead.
It may not be an issue with the USB controller although the description does
align roughly with the results of the issue your describing. But it's still
just one possibility that isn't that terribly uncommon. There are many
reasons it might stop working. For example it could be your USB ports are
worn out. This is also not terribly uncommon. USB ports were really designed
to have devices inserted and removed frequently. As a result they can go bad.
Changing ports might resolve that sort of issue too.
Internal cards and there ports aren't going to wear out generally speaking as
the cards don't get inserted and removed frequently. Doing this though does
have an impact on such devices/slots/connectors as well though if you were to
insert/remove a card/connector frequently day after day for several months.
Ultimately I'd go with the 34mm PC Card if replacing the internal card was
not an option. The 34mm PC Card uses the same highly desirable PCIE chipsets
that are used internally. It's just an external form factor now. They are not
quite as good as the internal cards, but still, better than the USB option.
