sound won't play when i transfer videos to computer

hi,
got a sony dcr-dvd 205e,when we transfer videos into laprtop and we open the videos they show but there is no sound.
Why? what we have to do? tx

What software are you using to play the videos?
It is most likely that whatever that software is it does not have, or have access to, an AC-3 (Dolby) decoder and as such cannot reproduce the sound. Your cam records sound in Dolby.

windows media player or something similar,shall i use another program?

The software supplied with the cam should be Dolby capable. Are you using that to transfer? If still not then;
do an internet search for "AC-3 decoder" and you should find a freebie that will allow you to hear your vids.