After 9.04, sound configuration has no setting tab for beep sound. I found some other interface for disable the beep sound. I memo how to disable it. We need just one line add to /etc/modprobe.d/blacklist.conf. sudo echo "blacklist pcspkr >> /etc/modprobe.d/blacklist.conf After doing this command, you needs re-login then your computer will not make noise.
I don't know....... You don't know........who know.....???