Audio to receiver

[Stu55]

Just put together an htpc with old parts i had around and everything is dandy except I am not getting any audio, I have it hooked up htpc->receiver by the way of the optical out on my motherboard. I have the video hooked up by my dvi to hdmi cable from my 7600gt.

windows 7

Am I going to have to get a sound card?

I am a newbie when it comes to this stuff a little bit too so...

 

[Ruiner]

Assuming Realtek,
Make sure 'digital out' is set to default in control applet and level is not muted.
Set output to something your receiver can handle (mine won't take more than 24 bit /44kHz, for instance).
What drivers are you using?