Disabling the Hardware Beep is different from system to system. In this article I will show you how to disable the Hardware Beep / Bell in FreeBSD and PCBSD.
How to disable the Hardware Beep in PCBSD and FreeBSD:
Type this in your terminal, as root:
# sysctl hw.syscons.bell=0
This setting not persistent. To disable the beep permanently, append this line in /etc/sysctl.conf, as root:
# echo "sysctl hw.syscons.bell=0" >> /etc/sysctl.conf
To turn the beep back on, use sysctl hw.syscons.bell=1
If you have Linux, read here how to disable the Xorg beep permanently.