I had a problem with another brand. The issue was that Vista wanted to pick the driver and it chose the wrong one.
I ended up only loading the drive from the install disk. Then attaching the antenna
. Then going into the control panel
, system, selecting the antenna
from the USB list, and then changing the driver to the correct one.
Now, that leaves you no icon on the desk top, but lick on the start button, select Connect To and you should see available WiFi
Your problem may be different but this is worth a try.