USB External hard drive malfunction

The only thing clear in your post is that the hard drive is not working.

Do you mean the drive is not recognized if you remove it from the external case? Do you mean the drive will work over usb if you change cases?

You might also get better and faster results by posting this as a question (use the Ask a Question half of the button).

You could try the solutions suggested in these questions:
- https://www.techrepublic.com.com/5208-6230-0.html?forumID=101&threadID=224200&tag=rbxccnbd1
- https://www.techrepublic.com.com/5208-6230-0.html?forumID=101&threadID=218095&tag=rbxccnbd1

And like Nick suggested, you will get a better response for this in the questions section.