It sounds like the circuitry is burn on the pcb board for your drive case. The hard drive may still be good and accessible but you would have to order one of these and plug into your usb port to access it:http://www.newegg.com/Product/Product.aspx?Item=N82E16812119152
Or you can buy another hard drive enclosure and put the hard drive in it. Your device may still be under warranty but the issue is you wont get your data back. What I am suggesting to you is to help you recover your data 1st. If you have no data you have to have then just rma it if its still under warranty.
If that hard drive is a 3.5" you could install it in a desktop pc and recover your data that way.
If none of this works then the hard drive could be bad too. Hope that helps...