Quick question -
how does it work when you display a Powerpoint presentation that was originally generated on a desktop computer (@ 1280 * 1024) on a 17" laptop screen running at 1440 * 900?
Does the aspect ratio switch screw up your images, or do you have blank areas on either side of the screen?
When you run it as a PowerPoint show it should fill the screen regardless of the size.
In my experience, there are black, blank areas on either side of the presentation image. I haven’t looked, but there may be a “fit to screen” setting to expand the 4:3 aspect to a 16:9. We usually use a projector so you don’t see the blank areas.