I appreciate the folder information. If I understand you correctly, should the same thing happen again, I will be able to start FSX without a long restoration. But after swapping the file I will lose the GSX program
Yes, but that's not a problem. Try to DO the Stand-Alone Addon Manager update as I've explained first, knowing that you can always go back to a running FSX with those file, and then we'll deal with GSX.
Maybe I should have asked what happens if I remove the entire GSX program and just re-install it?
Won't make any difference: the same set of files that needs to go with the updated bgmanx* files are contained in the Stand-Alone Addon Manager, which is why I only mentioned THAT one.
THe GSX installer installs exactly the same thing PLUS all its vehicles, but it's otherwise entirely identical to the Stand-Alone Addon Manager. You can call the Stand-Alone Addon Manager a GSX installation, sans the GSX vehicles/texture/liveries/sounds, but the important files are the same.