Make sure the power for your connected equipment is turned on.
If you've connected a computer and one or more video sources, you may need to press the Source Search button on the projector or the remote control to select the image source. Allow a few seconds for the projector to sync up after pressing the button.
Try restarting your computer.
If you've connected a laptop computer, make sure it's set to display on an external monitor.
If you're using a PC notebook:
Hold down the Fn key on the keyboard and press the function key that lets you display on an external monitor. It may have an icon such as , or it may be labeled CRT/LCD. Allow a few seconds for the projector to sync up after pressing it. Check your notebook's manual or online help for details.
On most systems, the key lets you toggle between the LCD screen and the projector, or display on both at the same time.
If you connect the notebook while the projector and computer is already turned on, the function Fn key that changes the computer's image signal to external output may not work. Turn the computer and the projector off and then back on again.
Depending on your computer's video card, you might need to use the Display utility in the Control Panel to make sure that both the LCD screen and external monitor port are enabled. See your computer's documentation or online help for details.
If you're using Macintosh OS X:
Select System Preferences from the Apple menu and click Display or Displays.
Click Detect Displays.
Do one of the following:
Mac OS X 10.6: Click Show displays in the menu bar.
Other versions of Mac OS X: Make sure the VGA Display or Color LCD dialog box is selected. Click the Arrangement or Arrange tab and make sure the Mirror Displays checkbox is selected.