No Audio on Transferred Videos

I have spent two hours (twice now) transferring videos from my HDD camera to
this new computer and I can't get sound! The error message tells me that
Roxio doesn't allow sound and I need to spend another $70 to upgrade to a
program that will allow me to hear my children on the video.

What's the deal? My XP software worked fine right out of the box. I can't
get any of the programs on this new VISTA to allow me to hear the audio on my
video. AND - to make things worse - the HDD is FULL and I can't record
anything else until I remove all the video on the camera, but I'm afraid to
do that until I know I have sound on the computer versions!

Please HELP!