Sometimes it is hard to get an available media projector. I've find a solution to overcome the lack of media projectors.
I've installed a VNC server on my laptop, only with view permission for remote users. In the computers of the room I've installed a simple vnc viewer.
The students just have to run the client to connect to my laptop. Then I just teach was usual, without pointing to the board ...
Students said that this method is better, since they view better on their screen, than on the projection board.