cant get sound from camcorder

Hello - fairly new to vista- trying to downlaod from MiniDV camcorder - video is great but no audio. using Firewire into USB port in new HP multimedia computer with vista home premium. Any help would be appreciated - even if it is just so say which software will be best to purchase due to issues with software loaded by HP -that is supposed to work. sound works just fine pluggin the camcorder via RCA jacks directly into TV.