I also tried cleaning the registry. Seems there was some Arturia "garbage" in there from a previous user or something. Rebooted after the registry clean and plugged the Keylab 88 back in. Still nothing. As far as Windows is concerned the device just does not exist.
It's frustrating and disappointing. Was hoping to have this working for an online meeting today... but not going to happen.
I just don't know what else to try, short of removing or wiping the Windows hard drive and starting over, which is at best an entire weekend's worth of work to then re-install everything, which BTW I may or may not be able to do with my Arturia software since I can't log in to the website (though the Software Center works fine and updates my software as it should).
There has to be some other solution here.