No Sound On My 360

[Stg-Flame]

Prior to building my new PC, I played my 360 through my old PC monitor and speakers. I also used a sound card in my old PC to which the green and black 3.5 mm jacks were used for my speakers and the 360 without problems. With my new PC, I have forgone the sound card since my motherboard comes with an on-board 5.1 chipset. I do not mix music, so I see no reason to use one.

Anyways, I tried all six of the 3.5 mm jacks in the back of my motherboard, and none of them will route the sound on my 360 through my speakers like they used to on my old PC. Does anyone know what is wrong and how I can fix it?

For reference, I have an ASUS P5K PRO motherboard and using Vista 64-bit (if that matters).
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Wolfdale e8400 @ 3.6GHz OC'd | 4GB Mushkin RAM | eVGA GTX 260 896MB VRAM 576/1242/1998 OC'd to 732/1457/2360

 

[mpilchfamily]

There is a line in jack, make sure the sound is plugged into there. Then go to your sound properties and make sure the sound is configured for 2.1 or just stereo sound. If its configured for 5.1 then the line in is being used as one of the speaker channels. Also make sure the line in is not muted.

Unfortunatly i'm at work right now so i can't get in front of my Vista system to give step by step instructions.