no sound?

[coughtryb]

My buddy gets sound just fine playnig audio CDs with his BENQ CDRW/DVD combo drive, but when he plays movies there is picture with no sound at all. I've tried several different players and looked through every setting and control panel that i know exists, from BIOS to device manager, to settings within the players themselves. all same behavior.

we've already tried installing that little gray digital audio cable to the drive.

any suggestions?

intel p4
WindowsXP
onboard sound

Thanks friends!