Mercury and SMTP Not Working

[RobberBaron]

The Mercury Mail application that comes with XAMPP opens when my computer starts and closes, and all it does is open every window it can. If I try to send a new mail message, it says it sends but I never receive it (I send it to my Google Mail Account). When I go to localhost/xampp and click status, it says SMTP: Deacticated. In my XAMPP Control Panel it is turned on, but doesn't seem to work. Also, how would I recieve mail sent to postmaster@localhost anyway?