If you can see it under Device Manager as working and not in My Computer at all you will need to undo any partition and then do a quick format to get it to work. You should also notice the LED not flashing before you do this. I JUST did this to two different HD's. One was a Passport and the other a My Book.
I right clicked on My Computer, clicked on Manage, then on the left you will see Disk Management. Click on that. You should see ALL of your HD's as well as your Burners. Right click on your "broken" HD and delete volume. It should go Unallocated. Right click on Drive again and format with a quick format since you have no data on it anymore. It should work. Good luck!