My SMART board has connection problems but everytime I unplug and replug it, the light would come back on and things were fine. I have tried different ports and disconnecting and reconnecting, but nothing seems to work.

The problem could be that the computer is turning off the USB hub, try taking a look at the device manager:

Control Panel
System
Hardware
Device Manager
USB Root Hub Properties
Uncheck "Allow the computer to turn off this device to save power."

When I turn on my data projector, no image appears on the screen. My laptop computer appears to be working fine, and the VGA (computer) cable appears to be connected properly. Still, the only thing that shows up is a blue screen and the words "no signal". What's wrong?

It's possible that you need a new VGA cable. It's more likely, however, that the projector is not receiving a signal because the output port on the back of your laptop has not been activated. To activate the port, look for the little monitor symbol on the top row of keys on your keyboard (often it is F7, but will vary with make and model). Simultaneously pressing this key and the function (Fn) key should activate the port and solve your problem. In some cases, it may be necessary to press the two keys a second time in order to make
the image display on both the projector and the built-in laptop screen.

My data projector was working fine, but now it projects an image with a pink (or green) cast to it.

One of the pins in your VGA cable (the cable that connects the computer to the projector) is bent or missing.
A new cable should solve the problem.

When I touch or write on my SMARTBoard, the mark appears several inches from where I touched the board. Why?

The SMARTBoard has lost it's orientation. This problem is more common with mobile systems than installed systems, but it can occur in almost any situation. If the SMARTBoard is on a mobile stand, make sure that the leg braces are in the extended position with the wheels locked. Then open the start-up menu of your "SMARTBoard Tools" software, click on "orient" and follow the standard orientation procedure.