If your not hardware aware ask a friend with experience to do this for you.
1. Take the hard drive out of its the USB unit.
2. open your computer and try connecting it directly.
or
If that doesn't work for you maybe the board on the hard drive is damaged, but it possibly can be replaced with a second hand duplicate model you find on eBay, I've done this before and has got me out of trouble.
Best of luck friend.