I got the same thing - my computer would charge the device, but not recognize it to allow file transfer. it was the same for all USB ports. I tried using the USB cable from my old Samsung YP-T9, and it actually worked immediately. So it is not the device itself, but the USB cable, for some reason. I don't know how to solve the problem with the HTC HD2 cable, though.
Answers & Comments
I got the same thing - my computer would charge the device, but not recognize it to allow file transfer. it was the same for all USB ports. I tried using the USB cable from my old Samsung YP-T9, and it actually worked immediately. So it is not the device itself, but the USB cable, for some reason. I don't know how to solve the problem with the HTC HD2 cable, though.