Follow these steps:

Someone has turned the red power switch located at the top of the cabinet off. This switch should never be used. After turning it on wait a few seconds and try our system again.
In order to turn off the system please press and hold the display button until the green light beside it starts to blink and you see the projector turn off.
You are probably forgetting a few things, if you are using a Dell laptop, while the computer is plugged in you should hold down the function key and pressing F8. On an IBM it is function F7. And will vary from system to system. On a Macintosh the proper way to use our multimedia rooms is to plug it into our systems before you turn it on. If your Macintosh has OS X as your operating system you can go into your system preferences and under display properties there will be a place to detect another monitor or output.
If the projector turns off that means it didn't receive any changes in inputs for at least an hour. Most likely you muted the image and went on to talk for awhile. This will cause the projector to go to sleep. If you know you are going to talk for more than 10-20 minutes before using the system again please turn the system off. The bulbs cost $450, so leaving them on is not encouraged. But if for some reason they projector does seem to go to sleep do not climb on a chair a press the power button on the projector, in fact that won't work in less than a month because we are disabling the control panels on the projectors to discourage this practice. The proper way to get the projector back on is to turn the system off, wait 2-3 minutes and turn it back on with the control panel. Please do not stand on furniture to do this!
Our document cameras are a little different, they don't have a button to do this instead if you want to move the arm down push it towards the back of the machine until you hear a click or until it stops then pull it forward and it should drop down. In order to put it back pull it up and move it full movement back until there is another click then pull towards you and it should catch. Please do not unplug and move the equipment.