I may have confused the point. Let me explain. I can plug my speakers into the green plug on my motherboard and the speakers work. I can't get any sound out of the front of my case, even though I have connected the HD plug and then changed it to the AC'97 plug. I get the same thing with either plug. No sound out of the front of my case, but I do get sound out of the back (direct motherboard connection).
One more thing. My motherboard owners manual shows a screen that should come up when I click on the speaker button on the bottom right tray. When i click on that, I don't get the same detailed menu that is supposed to be used to set up sound for AC'97.
Last thing. I don't think I have the latest BIOS for my motherboard. I have not flashed it. I don't know if that may be part of the problem or not.