External HD wont show up on pc

[moose_knuckle]

Ok, so I brought my external HD to my parents house to give my sister some family pictures and when i brought it home the next day it won't show up on my computer.

The computer sees that a device is present under "disk management," in the "other devices" category. I figured it was just a device driver that was the problem so i went to the acomdata website and downloaded their usb 2.0 driver and restarted. The computer still wont recognize the hard drive. To make a longer story short heres what I have done and checked:

1) Restart HD and all connections including different USB ports
2) brand new USB cable and power supply
3) installed new driver and tried device on multiple computer with the same problem.

At this point im at a loss. The hard drive will still powerup when i plug-in the USB cord, but wont stay spinning (i believe thats because the HD doesnt believe its plugged in or something? no?). The drive is a Acomdata HD500UFAP and the desktop PC i have is running windows vista 32-bit. Any and all suggestions are welcome

Thanx for the help in advance

 

[moose_knuckle]

Thanks for all the help. Awesome site

 

[drescherjm]

What did it look like in disk management? My guess is nothing was wrong but windows did not allocate a drive letter automatically. However it could be that the external is password protected and thus it requires you to install some software to decrypt the drive so that you can mount it. Does the external require a password?

 

[moose_knuckle]

In device management it just shows an extra drive. Ive attached a pic i uploaded of what i see in device managment and I think the other HD it is showing is mine, but I dont get why it would only be 16GB when the drive itself is 500GB. Heres a couple links showing what im seeing when I click on the device and what the computer is showing.

http://img442.imageshack.us/i/diskmanagementk.jpg/

http://img831.imageshack.us/g/deviceman.jpg/