Someone introduces you as the next presenter. The audience sits expectantly, awaiting your arrival. You step up, prepare to begin your talk, launch your presentation and nothing appears on the screen. Or equally disconcerting, no sound emerges from the speakers....

Think it can't happen to you? Think again. I hope it doesn't, but if it does, here are some things to check.

1: Is the projector plugged in?

Of course you have checked the end of the power plug that goes into the outlet or the power strip. Make sure, though, and follow the line all the way to the end. If you have a number of cords going into a strip, it's possible that yours, the one for the projector, might have been disconnected. Also, remember that old song that Judy Collins sang, "Both Sides Now." Check the OTHER end of the power cord. If it isn't hard-wired into the body of the projector, it will have a plug connection. Make sure that connection is in place as well.

2: Is the switch turned on?

I'm really sorry if these first two points are insulting you, but they're too important to skip. Make sure the switch to the projector really is On. Chances are, the projector uses the international symbols for On and Off. Keep them straight by remembering that the symbol for On, the vertical line (|), looks like the number one, which is close in spelling to on.

3: Is the outlet live?

Even if the projector is plugged in, and even if the switch is on, the projector might not be getting power. Check any power indicator lights on the projector. If there aren't any, check the outlet itself. Are other devices from the outlet or strip getting power? If so, your projector should as well. If your projector is the only device, test the outlet or strip by using another device. Remember too that a strip itself can have an on/off switch.

4: Is the video connection physically in place?

Your projector needs more than just electric power. It also needs video signals from your computer. Usually, that connection comes from a cable with a D-shell connector or a USB connection. Make sure it's in place and it's tight.

5: Is the computer sending a video signal to the projector?

Maybe a video cable is in place, but your computer might not actually be using it. The computer might not be sending a video signal to the projector. To resolve this problem, look on your keyboard or in your computer documentation on how to enable such sending. For example, on many Dell laptops, pressing the function key along with the F5 key toggles the display mode from PC only to projector only to PC and projector simultaneously.

6: Is the projector set for input from the computer?

Even if the video cable is in place, and even if the computer really is sending a video signal to the projector, the latter might not be expecting it. Such displays often are designed to receive input from other sources, such as a DVD player. You may need to use a setup menu for the projector to change the source of input.

7: Is the projector sleeping?

Projectors often are equipped with an energy-saving sleep or hibernate mode. In such cases, hitting the power button once or twice quickly will take the projector back to active mode.

When I'm working with a projector, I try to avoid putting it into (or allowing it to go into) a hibernate mode. Instead, if I want to hide the projector display from the audience, I will simply put a piece of paper against the lens or loosely cover the lens with a lens cap. I want to take no chances with the projector and its hibernate mode.

8: Forward or reverse projection?

Projectors generally are set up so that they display images from the front of the screen. However, sometimes, for aesthetic reasons, you might want to display images from behind the screen. In that case, the projector needs to display images “backward.” If you see such backward images, check the forward/reverse projection setting.

9: Right side up or upside down?

Similarly, projectors can be designed to hang from the ceiling. In such cases, they are upside down, and their displays have to be adjusted accordingly. Therefore, if your image appears upside down, check the appropriate setup menu on the projector.

10: Is the display resolution compatible?

If you're still getting no display, make sure that the projector can handle the resolution settings of your computer. You might need to make your computer display less fine - that is, setting it to lower numbers. You can do so in Windows via the Control Panel Display icon (in classic view) or via the Change The Screen Resolution task under Appearance And Themes.

11: Are the sound settings correct?

If you're not getting sound, the problem could arise in any of three areas. First, look at the application that's generating the sound — for example, Media Player. Make sure the volume setting is greater than zero. Second, check the sound settings for your computer itself, via the Control Panel's Sounds And Audio Devices applet. Make sure that the volume here is also set to greater than zero. Most important, make sure that the Mute option is not selected.

12: Are you using the right sound jack?

If you're planning to get sound by plugging a 1/8″ minijack cable into your computer, make sure you're plugging the cable into the headphone jack, not the microphone jack. The latter might be labeled with a headphone icon, and it probably will resemble the letter “C” on its side.