Recently, after a few days of uptime, my sound would completely go out on my laptop with the only thing fixing it being a complete restart of the machine. I originally tried:
sudo /etc/init.d/pulseaudio restart
This did not work at all, so I resigned myself to just restart the machine when it happened. With a solid state disk, rebooting takes 30 seconds, so it was not a major pain. But the sound went out again today after only about 2 days, so I decided to see if I could fix things. I decided to run VLC on an audio file from the terminal to induce some error messages. After playing the song for a few seconds, the terminal began to be flooded with messages like:
[0xdf11a0] pulse audio output error: overflow
Aha, it was in fact a pulseaudio problem. So, the following steps fixed my problem.
In a terminal:
sudo killall pulseaudio
Then, Alt+F2, enter pulseaudio in the box, click Run, and boom sound was back in action.
Hope this helps someone.