Passport Ultra not recognized

I have read this forum, tried everything, and I still can not get my external HD to recognize. I used it last night, worked fine. This is less than 2 months old, with thousands of documents. Reimaging is not an option. It is spinning, light continues to blink but it will not show up in Device Manager or My Computer. HELP

Welcome to the Community.

is the hard drive password-protected? Have you tried replacing the USB cable or using it on another computer?