I had the same problem with this board. I plugged into the green jack (center bottom or right depending how you look at it). The realtek audio manager pops and asks for the device plugged in. I selected rear speaker thinking it meant the speaker jack on the back of the case. But I think it means the speaker behind you in surround sound 7.1 not which jack. Then I unplugged it and plugged it back in and chose front speaker and it worked. If you select rear speaker and surround sound 7.1 it works too, when the sound test gets to the rear speakers.