Isnt S-video is for video only? you have your audio outlet from the player for sound? Not sure though, just check again.

(i have no idea how to transfer the sound so i connect the RCA L-R to the onboard sound hoping it'll work..i connected them to every available connector thingies on the back of the PC..)

These are audio-out from your cam to your input audio to the sound card? There's sound from the cam on its own?
Try out the wires/cable settings to your tv and check if both working. Your cam audio head maybe dirty and not giving out sound.
FYI, I'm just guessing may not be worth your while for all the hassles>