i guessing here. problem is probably on the hardware layer. not enough power comes to mind. make sure the case's external power source or dual-USB connector is plugin. wat it may be detecting in Hardware Device is the interface.
imho, under Computer Management > Disk Management, the bottom half should b software independent. regardless of the data on the drive, it should show up as Disk 0, Disk 1 or Disk 2.
if it missing on the list at the bottom half panel, i suspect it's a hardware issue on the disk or cases.
The two usb cases that i tried do have an extra usb plug for the extra power..
Just strange that I can see the drive under device manager and the icon for safely removing usb device both shows the drive.. but nothing under disk management
just tried doing a low level format on the drive but it shows a few error constantly ..on areas of the drive.. it seemed to format it but not sure if it was done correctly due to the fact that I tried to partition the drive using easuse partion and it failed to write the info to the drive...