One of the most common problem beside accidently deletion (which
i believe it's not in this case) is that you accidently click and
drag the entire folder into another folder. Since when you
drag the folder to another folder, even if the folder being dragged
is 100GB, it won't matter and can be done within a second.
Can't you use your Windows search function to search for the
song files to check if they still existing in your drive?
If can't find, then I think that part of the harddisk may be
corrupted, and so it can't read the data.
