Capture video has no sound

> Hello,
>
> I have just purchased an HP system that has Windows Movie
> Maker already installed. I am trying to caputer a video
> from my Sony Handycam using the SVideo cable and audio
> using the composit cables (White/Red). I am able to
> capture video but without the audio. I know my system
> works because I can use another program that came with my
> PC called arcsoft (i believe)and it captures both video
> and audio. I would use arcsoft but I do not like its
> editing tools. Can someone tell me what I am doing wrong?
>
> Thanks in advance,
> jmb