A big oh boy howdy and thanks to all who responded to my call to arms concerning the non-functionality of my MSSFFP joystick with XP. As it turns out, it finally came down to a non-destructive recovery of the whole system, and I'm happy to report that everything now works beautifully including not only the joystick (which is simply plugged into the ol' gameport) but other little odds and ends that just weren't quite right.
We all dread a recovery, but this one paid off in spades! So far, everything is AOK, and once again I'm soaring with the eagles.
Mucho gracias, mi compadres!
San Pedro, CA