I just installed Ubuntu today. I'm testing everything out and it seems pretty cool so far. There's just one big problem. The audio suddenly stopped working. It worked just fine when I first installed the system, but it has stopped for no reason that I can determine.
I don't like to use proprietary software (though I will if I have to), so I removed these packages:
firmware-crystalhd nvidia-libopencl1-331-updates nvidia-opencl-icd-331-updates. But they don't appear to be the problem, because reinstalling them didn't fix the problem.
I checked alsamixer, and it looks rather different from what I'm used to: http://i.stack.imgur.com/qF6iW.png
The "Sound" settings in the system settings aren't too helpful, but here's another screenshot just in case: http://i.imgur.com/W65OLMd.png I can't move the slider, and there's no sound devices listed.