The computer was getting worse and worse, and it wasn't just the sounds. The whole thing was bogging down. I think it has been three years since the last time I used the system restore discs, so I guess it was overdue (this computer is five years old, or so). It was a lot easier this time since I now have a second hard drive to stash stuff on.
The machine is zipping right along now and playing mp3s like nobody's business. I just need to get the latest updates for various important programs and then I can make a full backup of a fresh system.