Pat wrote:
I clicked on it and was instructed to remove the batteries, press
every button once, repeat for every setting of the two slide switched
and then reinsert the batteries. I was very skeptical, but sure
enough, it works fine now.

Maybe one of the buttons or switches was stuck on, or had some goop
(beverage, etc) shorting the contacts, and operating the buttons
cleared it? I've seen a remote where a button could be stuck on, but
it was hard to tell by inspection that it was lower than the adjacent
buttons.

Matt Roberds