I had the same problem when I first got mine. Have you set the playback STD to HDV?
Set big knob to VCR/PLAY, hit menu button, in VCR Menu select signal setup(push to the Select/set) button at the back left bottom of camera, scroll down one option to Playback STD, push the select button again, you should see auto, HDV an SD. Select HDV for HDV! Use the menu button to escape. Turn off your camera, plug it in, turn on camera and it should be sensed by the computer.
hope that helps
