Sound theme problem after upgrade

[gap]

Upgraded from 10.04 to 10.10 using standard Update Manager procedure.

Now I get a sound (thump) in my speakers for almost every button click. The sound theme in System / Preferences / Sound is "No sounds". I would like to completely disable any "activity" sounds from the OS, but nothing works.

Please help.

[gap]

This problem seems to be related to this one:

http://ubuntuforums.org/showthread.php?t=1593428

See bug report:

https://bugs.launchpad.net/ubuntu/+source/ubuntu-artwork/+bug/649809

[dino99]

install gnome-alsamixer and set your prefs