I have a 160G WD Passport. When I plug it in the USB connectors on the
face of my PC my Vista wasn't able to identify the HDD.
I plug the device in the USB connectors on the back (are on the MB - no
cable between) and I have no problems.
So in my case was not a problem of Drivers but probably was a problem
with the power over USB.

Note: the HDD works on my laptop w/o problems.

Try one of the following:
1. Identify another USB port and try again
2. by an USB cable with 2 ports: one for power and one for data.

bsrgs,


--
Darlock