I don't know anyone that has ever made that work. FireWire works pretty much all the time. The only thing the USB connection might do is allow you to transfer stills off the memory card.
You need to add a FireWire/IEEE1394/iLink/DV port to your computer. You need a FireWire cable (4-pin camera side 4 or 6-pin computer side - it depends which FireWire card you get).
Adding the port is not difficult and the card is not expensive...
When I bought this camcorder I was told I could transfer video from the camera to my PC using the USB wire included in the package. i was told the quality may not be good, but that I could still do it. I have tried and tried, but I cannot seem to transfer video to my PC this way. I've installed the drivers, I've even captured pictures from the DV tape through DV studio. But when I open the bundled video software from microsoft, it doesn't recognize my camcorder. I have windows xp professional and office 2007! Anyone know how to do this?