It's possible the chip that performs the above has died. Just to be sure, reload the software it came with to windows and see if that's the problem. If the case and it's board has failed, some of those can have the drive pulled and read directly when hooked to the motherboard with a data and power cable, some can't, don't know about that one.
That comes in an "old" model and a newer one. If the case has failed, you might be able to insert in another Passport case of the same model and get the data off.
So i have been using a 2 TB Western Digital Passport as an external hardrive for the last few years. Recently when I plug it into my computer, it does not allow itself to be read. To make it show up on my computer, the window have to be refreshed and it goes through a infinite index search mode. While the harddrive is plugged in, I have freezes in explorer.exe and all internet is down. Ping command from command prompt still works fine. When viewed in task manager, it shows the drive have 0mb formatted. Can someone tell me whats wrong with it?