Corteney,
Depending on the operating system the teacher is using, ensure that the display settings on the computer are set to "Clone" on Windows computer and "Mirror" on Mac. Also, depending on the size of the board, ensure the resolution of the computer is set as follows:
64" or 78" board = resolution 1024x 768 with 60 hz refresh rate
87" board = resolution 1280 x 800 with 60 hz refresh rate
95" board = resolution 1280 x 720 with 60 hz refresh rate
Hope this helps!
(case# 285877)