I have a Soltek-K8T-Pro939 motherboard and it has a Realtek ALC850 AC'97 2.3 8-Channel with UAJ, SPDIF optical in and out onboard audio sound card. However when i plug all the speakers in, it only plays the FRONT left and right speakers and the sub. I'm using the realtek sound manager. When i do the autotest it plays all of the speakers so i know the speakers arent broken. The center speaker and the rear speakers dont play my music. I'm not sure why this is. Below is a picture of my motherboard and the sound card. I'm plugging all 3 of the logitech cords into the 3 vertical ports to the right.