Hi alexphill ,
Here are the things you can try to resolve this problem.
One of the reason why the FN+ F5 is not working is
the projectors resolution doesnt match the resolution of the system. Maybe the resolution of the system is much higher than what the projector can take,
Try lowering it down or play with the display settings.
To change display settings ( For Vista )
1. Open Display Settings by clicking the Start button , clicking Control Panel, clicking Appearance and Personalization, clicking Personalization, and then clicking Display Settings.
Hopefully this should work
