Strange audio problem

WinXP Home SP2 - clean install - Acer laptop Aspire 5670 - Realtek HD Audio
All the drivers installed without any problems, and if I plug headphones into the headphone jack, there's sound, but no sound comes out of the built-in laptop speakers. I have checked everything, and I've looked everywhere, and found nothing. The Acer web site even had a driver that said "Fixes mute on restart problem." and I though "YES!! Problem solved!!". Nope. Problem not solved. The sound comes through the headphones just fine, but not through the speakers. Everything tells me there should be audio, but it just isn't there. I think that maybe the speakers are bad (???). Anyone?

 

I've checked everything that could possibly mute the speakers, and none of them were on. There's a Fn + F5 or F6 combo that toggles the speakers on/off and I toggled it a few times and it made no difference. I could see that it was working: the little speaker in the system tray by the clock would get the red-circle-and-red-line symbol when I toggled the mute on, and it disappeared when I toggled it off, but I didn't do it a bunch of times, only 3-4 times. Maybe I'll do it a bunch more and see if it helps.... Thanks plodr!

 

Maybe the headphone jack is not re-closing and completing the circuit. Have you checked that?