3 courses of action as I see it if you want to save the music files.
1) Use your xp disc to attempt to repair the existing system, may work ok.
2) Buy a new pc install xp then plug the old hard drive in as a slave and either keep it as a second storage device or copy the files across.
3) Buy a new "el cheepo" hard drive plug it into your existing machine in place of your existing drive, install windows, then proceed as above.