Let's talk here about using projectors and what we need to know to use them well.

Pic-mute is a favorite projector option of mine. Look on your projector remote for a special button that allows you to temporarily cut off the projection. This is great for when you want students loooking at your face--and not the board, or for when the board is set up but you do not want them to see the image yet.

Source--is an important projector feature. If the source button is accidentally hit, your projector might report "no signal." Try hitting the source button or the "RGB" button (it can also be named "computer" on more recent remotes) to remind the projector that you want it to be connected to the computer and not some other piece of equipment.