GOOD NEWS!!!
I did the "disconnect the battery" version of the reset tonight and now everything works again!
The Pass-Key is now displayed, so I can pair my phone!
The System Reset option is back!
The Master Reset button is now there (but I don't need it, of course!)
Sync recognizes the USB drive, so I can install the firmware update! (Haven't done that yet, but I probably will.)
And there are more goodies that I don't think I've seen before!
So I guess Microsoft's equivalent of Ctrl-Alt-Delete for Sync is "disconnect the battery cable".
