There are a number of approaches for a system-wide fix, disable PC speaker beeping.

Approach 1: Disable the kernel module; edit the file /etc/modprobe.d/blacklist (comes into effect after reboot);

# turn off the PC speaker
blacklist pcspkr

Approach 2: set the bell duration to 0 milliseconds, for all ttys. Edit /etc/rc.local (comes into effect after reboot);

for i in 1 2 3 4 5 6
        setterm -blength 0 > /dev/tty$i

Note the approaches here should work with most Linux distributions

Note tips for this page come from http://ubuntuforums.org/showthread.php?t=422061