As above. System restore won't store the files, only the settings for the applications/registry entries that were current at the time.
What was the music program concerned, and have you any idea what file path it accessed the music from? It may, if she's fortunate, have left a folder behind that contains the music. Do a computer search for one of the file names (Say, "Frankie Goes to Hollywood - Relax.mp3") that you/she knows for sure was there. If it is still anywhere, that method has a chance to locate it.
If they have been deleted with the uninstall, a recovery program is the only answer.Don't use the computer too much (that is, install or uninstall programs, browse the web, delete temp files, that sort of thing) as it increases the chance the files will be overwritten, making recovery more difficult. You will, of course, need to install the recovery program. If you can install it to a different partition than the music program was on, that would be best, but from the sound of it it's unlikely that HD would have been partitioned.