Computer displaying to projector instead of monitor

Hi

I have an Acer Veriton X2632G in are office at work and we are trying to figure out why all of a sudden the computer will only display the monitor screen or the projector but wont do both at the same time. It will not let us duplicate the screens.

If we put the VGA monitor plugged in alongside the DVI to HDMI cable for the projector then the projector will display but the monitor will go into standby. If we unplug the projectors cable the monitor displays.

On Windows it will only display one at a time in display properties (where you change resolution & duplicate/extend) we cant get it to display both at the same time? If the projector is plugged in the monitor does not show up in the resolution screen.

Any ideas?
 


It will not show both displays in the resolution screen so it cant duplicate as it doesn't recognise both at the same time.