You could try removing the drive from the enclosure and attaching it to an internal port and power supply. If it's just an enclosure problem that might work. Don't expect too much though, usually when portable hard drives don't work it means the disk itself is bad. There are several data recovery tools like this:
You can take a chance with a free hard drive recovery tool that has ever helped my boy friend retrieve all his inaccessible data back. You can get more information from here: http://not-formatted.blogspot.com/2013/02/recover-data-... Important note: You should avoid saving new data on this drive before you have restored all your data back.
You should always back up your important data in the future.