[Ubutun] Repiar no sound problem on Ubuntu 16.04

Uninstall pulseaudio package

sudo apt-get purge pulseaudio

Remove the following files/folders

sudo rm -rf ~/.config/pulse /etc/pulse /usr/share/pulseaudio

Reboot you system

Reinstall pulseaudio package

sudo apt-get install pulseaudio

You might need to reinstall ubuntu-desktop if your 'Ubuntu System Settings' has disappeared

sudo apt-get install ubuntu-desktop