I did the steps in the first answer there, and when I rebooted there was no sound at all. In the settings it says dummy output. What Shall I do now ?! I do not want to follow anymore steps that will make the problem even worse. sudo apt-get install aptitude
sudo aptitude --purge reinstall linux-sound-base alsa-base alsa-utils linux-image-`uname -r` linux-ubuntu-modules-`uname -r` libasound2
I ran those two commands and I got my sound back. But the problem of the headphones not muting the rear speakers still exists!!! Can anyone help me with that?
Running Ubuntu 12.04