1800mp projector

I have an 1800mp projector hooked up to a latitude d520.  I am a school teacher who uses the projector throughout the day at different times but when I cut the projector off and later back on the remote control do not work.  I have to reboot the computer or disconnect the usb cable or run through the fnf8 to make it work again. and it does not always fix the problem.  What is the correct procedure to make the remote work.

how long does the projector have to be on before you boot up the computer. Help