So to recover I turned on hidden files and folders in folder options. Then navigated to:
C:\Users\YOUR USER ACCOUNT NAME HERE\Appdata\Roaming\.minecraft\Saves\
I found her game was still there.
So I recovered her game by starting a new one and then copying the new level.dat, level.dat_old and session.lock files into her lost game directory. I then deleted the new game.
I then started minecraft and her game was there and worked!