Reboot and try again.

What windows version

Can you get into it now?

Click start and control panel and administrative tools and storage and tell me if it is listed there if you cannot get into it still.

So when you click on my computer does it show in the list of drives?

What operating system where you using when you backed things up to this unit?

Lights work on drive?

When you unplug it does your computer make noise?

When you plug it in does make noise? "hardware found"

In the computer management screen in administrative tools under DISK MANAGEMENT, it is not listed? I am wondering about a couple of things:

1. Cables and hardware failures.

2. USB quirks.

For the USB issue do you have any other things that run on USB?

Go back to hardware manager and right click on the USB devices one at a time after opening them with the + sign and uninstall them. Then reboot the computer and they will be redetected.

For the cables and hardware, do you have another computer that you can try the unit on
?

Also what is the make and model of the one that we are working on?