Try moving the audio jumper (FP_Audio on motherboard), it might be set for rear panel only or something. Look up your motherboard and find what all the pins are, there should be 9 pins i think. I had an old motherboard that wouldn't play from the back panel, set pin jumpers correctly and voila, it started working. I didn't understand the whole process that well, why putting a jumper on such and such pins made the difference and why one would set it up that way anyway, but hopefully it at least gives you an idea of what might be the problem. Good luck!