I did a Clean Install of Ultimate Edition 2.4 just after it was released. I have Ubuntu 9.10 running on another drive, as well. When I uninstalled Nvidia 190.42 and installed Nvidia 195.22, the video was fine, but the Audio Output had some Static and a Whistle. It was not clean, like before.
I followed these instructions:
sudo apt-get --purge remove linux-sound-base alsa-base alsa-utils alsa-source pulseaudio
sudo apt-get install build-essential linux-headers-$(uname -r) module-assistant alsa-source
sudo dpkg-reconfigure alsa-source
sudo module-assistant a-i alsa-source
reboot
Now, I have no Volume Control icon and when I launch System/Preferences/Sound, I receive an error box that says "Waiting for Sound System".
The Audio Output is working and the sound seems to be clean, but I have no control over the Volume and no Mixer.