Earlier this morning I upgraded from Gutsy to Hardy.
After upgrading my sound system does not work anymore.

As I never had to do anything to get my sound system working I am not very familiar with this.
If anyone can tell me how to get my sound system working again, you will earn my eternal gratitude.

Regards,

Sjonnie48

Assuming you have a reasonably normal/common audio device in your machine, and assuming Ubuntu uses ALSA as the backend to drive your sound device, you might want to check the ALSA mixer settings to make sure the sound is not muted and the volume is turned on/up.

In a console (or as root) type "sudo alsamixer" (or "alsamixer") and using the SPACEBAR and arrow keys and the "M" key for mute/unmute make sure the PCM and master volume (as well as any other pieces that pertain to audio an your machine) are not muted and are turned up sufficiently.

When done, hit ESCAPE and then type "sudo alsactl store" (or "alsactl store") and now try the sound.

If this fails, provide us with info about the audio device, and anything else you can tell us about when it did work.

Sed fugit interea, non urinat in rectus uter.

I've run into the same problem, and the previous poster's suggestions will probably do the trick if your hardware was working before. If not, check out the following guide:

http://ubuntuforums.org/showthread.php?t=205449

It will walk you through the process of checking your hardware, kernel modules, settings, etc.

What a nice interface! Thanks for the help, I've got my sound working again!