To enable, disable, or change the sound made when a new email
arrives, type "Sounds" into the Start menu and select the first
option (Change System Sounds). In the window that comes up click on
the Sounds tab. then scroll down to New Mail Notification and click
You will see a drop down menu underneath called "Sounds:"
which you can click and scroll up to select None to disable, or
select a different sound to play.