I haven’t seen anyone with my specific problem, though GREENSCRABBLER was very close.
After installing a Windows update (7, 64 bit), my Passport stopped working. Now when following various suggestions on Windows and WD support forums, I can see my drive (LED works, feel it spinning as well), and Windows says it is working properly, but no files are present & even attempting to format the drive brings up an error message. I can do NOTHING with this HD.