1. Enable the external monitor on your notebook
Projectors usually connect to the external monitor port, which must be enabled before sending any image to the projector.
(1) Press and hold the “Fn” key (located in the lower left-hand corner of your keyboard), then press the “F3” key, which may be various from machines. (This combination of keys is known as "Fn+F3".) Each time you press the “Fn+F3” key combination, you will cycle your display through the following settings:
(2) Wait a few seconds each time you press “Fn+F3” to let the projector refresh or "perfect" its image.
(3) Cycle through the display settings using “Fn+F3” until you reach the setting you desire.
2. "Waking up" the projector
Some projectors have power-saving states similar to the computer sleep mode. Usually there is a button on the top of your projector to enable or disable this state. Consult your projector’s documentation if you need to "wake up" your projector.
Usually this problem occurs when your notebook’s display properties are set to a resolution that your projector does not support. Similar to your notebook LCD display, your projector has an optimal resolution with which it works best. Consult your projector’s documentation to find this optimal resolution and set your computer’s display properties accordingly.
Set the display properties on your notebook:
Your computer probably has a built-in feature that turns off the screen after a period of inactivity to conserve your notebook’s battery power.
Disable the power-saving feature that turns off your screen
For Windows 7:
Resetting your projector will fix most other problems.