Projector not showing the same as the Computer Monitor?
Sometimes a computer does not show the same image on the projector as on the monitor. This is usually the result of a cable previously having been unplugged.
For Desktop PC's:
This is quick and easy to resolve. On the Start Menu there is an icon in the ‘Utilities’ folder called ‘Duplicate Monitor & Projector Output’
This does exactly what it says, and should resolve the issue for you instantly.
Pressing Windows Key + P will open the projection menu where you can choose to duplicate or extend your screen: