I was having some minor problems with the audio on my machine in that when I connected to HDMI there was no option to play sound out of HDMI sometimes (as described by this thread No choice for HDMI audio output)
I followed the instructions in this post and installed Pulseaudio, which worked for that issue, but I then noticed that the standard sound settings and volume controls no longer functioned correctly (something which is more important to me than connecting to HDMI) so I removed Pulseaudio and then rebooted my machine.
After doing this not only is the system sounds not available but the system settings GUI is missing many of the usual entries (I only have Language Support, Security and Privacy, Printers, Landscape Service and Software and Updates).
I tried then to purge Pulseaudio and it had no effect and then reinstalled it also with no effect (although I am able to change the sound levels through the pulseaudio interface).
I am running V14.04
sudo apt-get install ubuntu-desktop
to install missing packages which may had been removed when pulseaudio removed. – user.dz Oct 06 '14 at 19:24