Hey there, Clarence_5.
Do you have any data which you need to recover from that HDD? Have you experienced any issues with the drive prior to this problem?
I'd recommend that you try the drive with a different computer and a different USB cable (preferably shorter than 12"), to see if the same thing happens. You could also try reinstalling or updating the driver for your USB controller from Device Manager, to see if that fixes things up. If you have a different external drive available, you could try it out with the same computer, to see if there's anything out of the ordinary.
If you don't need to recover data from that HDD, I'd suggest that you download the HDD manufacturer's diagnostic tool (or a 3rd party diagnostic tool if the...