Due to the proliferation of cellular phones and walkmans it's not quite common in our days to take care of a quiet environment. Anyway I want to give some recommendations for the polite ones.
For the console setterm -blength 0 and for X11 xset b off turns the bell off. See also PCMCIA-HOWTO, and much more details in the Visible-Bell-mini-Howto by Alessandro Rubini.
When starting your laptop with PCMCIA-CS configured correctly, this will be shown by two high beeps. If you want to avoid this put CARDMGR_OPTS="-q" into the PCMCIA configuration file, e.g. /etc/pcmcia.conf for Debian/GNU Linux.
To avoid the dialtones during the modem dialing add
module "serial_cs" opts "do_sound=0"
to /etc/pcmcia/config.opts (from man serial_cs). This will disable speaker output completely, but the ATM command should let you selectively control when the speaker is active.
usbmgr configuration file /etc/usbmgr.conf.
### BEEP # beep off # beep on
You may configure vi with the flash option, so it will use a flash in case of an error, instead of a bell.
For at least one laptop series, the Toshiba models, there seems to be a Linux package available to control the fan and other features.