GSX is not only installed but active as well....so I ran the FSDT update where I got another error message saying "trouble saving to XML file"
That seems to indicate something ( antivirus, most likely ) is blocking access to the GSX add-on.xml file, which must be updated for GSX to work, otherwise it wouldn't be able to find its objects. Try disabling the antivirus during the update.
Another possible reason is a permission problem, or an external utility that had access to the GSX add-on.xml file which is running, or possibly corrupted it. That ransomware you said you installed might have caused this.
Try this:
- Remove the Document\Prepar3d v4 Add-ons\Fsdreamteam Addon Manager folder
- Reinstall GSX
