Bob, I don't know of any normal condition that would cause your keyboard to act that way. I think you need to get it to a service center asap.
The only time I've had keyboards act in such a manner is when they had water or moisture in them. This was quite a long time ago, and not the PSR2000. After it dried out it resume normal operation though.
I would take a backup of some sort to the job! Wish I could be more help.
DonM
P.S.
You can copy the Swing and Jazz styles you need to a floppy and play them from there.
If you can't get to them on your keyboard, you can find them on the internet.