No audio in Ubuntu Gnome

[Lenny]

Hi,
After having total audio problems with Ubuntu Mate, I tried installing 
Ubuntu Gnome on this laptop, a Compaq Presario 2500, with a GB of RAM.
I had audio through the installation with the live DVD.
When I booted up and came to the log in screen, I did Super-S and control + 
S, and then had audio,
but it was very slow and choppy.
After booting in, there was no audio, I could not get Orca to run, or it was 
running with no audio.
I could get no sound with a backspace in an edit field.
I shut it down, and this time when I restarted the speech was faster and not
choppy.
But I still have no audio after logging in.
I tried the audio buttons on the side of the computer, and I tried control +
Super up arrow.
Is there a command to un-mute audio, in case it is muted, or a way to load 
another sound driver?
Thanks.
Glenn