Files no longer visible on my WD My Book External 4 TB Drive

I have aWD My Book External 4 TB Drive that I have attached to a Synology NAS for back up.  It was working great until about 2 weeks ago when I noticed I could no longer view any files on the drive.  This is true if I access the drive through a windows 8 cumputer or the Synology DiskStation file manager.

Anyone have any suggestions?



To confirm if the drive failed, try the steps on the link bellow.