As dj says, there are numerous (and several free) progs which will enable her to recover at least some of the music assuming the disk space has not been over-written since delete. Google.
As far as restore points go, you can delete what you like (I'm not sure about the last, though) but be VERY SURE you don't delete the very one/ones you need.
Sysrestore is NOT like a back up. She needs to back up the music to CD, DVD or other to be safe.