Can someone out there help me

I have a G3 powerbook 400Mhz which I use power point on for work. The G3
via the ext monitor port drives a data projector. I was ask whether it
would project DVD's, which it had but when I tried with a Hitachi
projector it wouldn't. No probs must be something with the Hitachi
project. But now I cant superimpose the LCD screen on the projector
screen in the monitor options. Its either left right top bottom but not
over like the options say.

have I screwed up or is it a software, preference problem

TYI

John