Open a command window by clicking on START then RUN then type in CMD. Press .

At the command window prompt, type each line EXACTLY as written below and be sure to press ENTER [ENTER] after each line.

>net stop beep [ENTER]

>sc config beep start= disabled [ENTER]
^
NOTE: The space between "start=" and "disabled" is required.

These two lines will disable the beep right away and it will not return unless you specifically enable it.

If you wish to disable the speaker only temporarily until the next reboot, just type in the second line.