When I upgraded to Juanty, my sound did not work on my laptop. I found a couple of posts that helped me get it back up and running.
I think I found this post from this one:
I have had trouble with the pulseaudio service not running, and so I did a little research to find the command to restart it. I haven’t tried these so be warned.
This article suggests:
pulseaudio -k; sleep 4; pulseaudio -vv
This article points out that you can use “pulseaudio –check” to see if an instance is running. Also, they mention that if the -k doesn’t work, you can use “killall pulseaudio”.
Finally, since I use Skype, I have been contemplating going back to alsa. I am not ready for that, but I am keeping this in my back pocket: