How to adjust screen on an external monitor.

If you are using an external monitor like a Television or a Projector and you are not able to see the menu bar at the top of the screen, then your settings are using overscan. This only happens when you are using the external monitor in mirroring mode (Computer and external screen show the exact same thing). You need to uncheck the Overscan option in your System Preferences -> Display. Click here for instructions.