Hopefully you like the music stuck in there if you intend to keep it...
Joke aside, if a restart didn't help there is probably little you can do unless you're into audio repair. Unless it is a highend unit you really want to keep, buy a new one. Or have a pro fix it.
What you can do yourself is open it and look for blown fuses, fried components, dried soldering points or other bad connections. I've repaired equipment ranging from cd players to huge CNC machines that way. Without being too skilled in troubleshooting electronic circuits.
Edit: I didn't realize this was a dumped thread; posting with my cell.
Dorothy, dumping very old threads isn't widely approved around here