The problem could be with drivers or something, but the best solution whatever the problem would be to change to using firewire transfer to capture your footage.

USB isn't any good for DV transfer, you'll only need a firewire PCI card (if you haven't already got one), and a cable, but you usually get one bundled with the card. shouldn't cost more than £15, and you'll notice a big increase in quality, and sound shouldn't be an issue either.

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P4 1GB Ram 50+160GB, Win XP, Premiere 6, Encore+Photoshop, Lite-on 4x dvd rw.
Sony TRV-250, Panasonic NVGS-75, Canon MV600i