pull it from the enclosure and hook it up directly to your computer.
before you do give the hd removed from the enclosure is a VERY light shake to see if you hear any metal pieces rattling inside. If so you are most likely screwed.
I've had this happen several times, with some being just adapters broken/pulled away, and others with hard drives completely failing. It's really a toss up on external drives, because they include more parts than just a bare internal hard drive.
You have just received the Amish Virus. Since we do not have electricity nor
computers, you are on the honor system. Please delete all of your files.
Thank thee.