I know this thread is a little bit old. But, I still want to share my opinions with you.
As I know, a hard drive is often damaged logically or mechanically.
The logically damaged drive often can be repaired after re-formatting and the contained data also could be restored with the help of data recovery program.
However, oppositely, the physically damaged drive often cannot be fixed and the stored data is also gone with the physical drive.
So, disconnect this drive to your computer and use a data recovery program to take a chance.
In order to avoid data recovery failure, you’d better not save anything else on the same drive. Anything new on the same drive could rewrite your inaccessible data and make it gone permanently.
And then, select a proper data recovery program to retrieve your inaccessible data back. I know there are some drive data recovery freeware available online, such as Recuva, TestDisk and iCare Data Recovery Free, etc.
If this really makes no difference, consulting an expert for help as soon as possible could be a really good way to go.
Good luck!