When I plug in a 64GB USB drive into my Vista, explorer hangs. I cannot do anything, and if I just pullout the USB drive it comes back to normal.
However with smaller USB drives (i tried with 1 & 2 GB) it works ok.
I'd suggest visiting the manufacturer's web site: the unit may not be Plug & Play functional with Windows Vista. See if the drive comes up in the device manager - if it does, but isn't available to copy files to in the FIle Explorer, check and see if another PC will recognize the drive. Otherwise you may have to format your drive by using the Format cmd.