Sure you can Cathy, even though it kind of a cheat. Start with a blank
slideshow and go to FILE>PAGE SETUP and change the layout dimensions for the
width and height from 10 X 7.5 to a 10 inch square.
The cheat is that you will need to create 2 sets of black "letterboxes" just
like on a widescreen DVD, one set for your landscape slides and another for
your portrait slides. By having a square shaped page layout you can
effectively create your own widescreen/landscape layout by putting a black
letterbox at the top and bottom of the square, or you can put the black
letterboxes at the right and left hand side of the square page layout and
just like that you have a portrait layout.
It's a cheat, but it works and I've used it a number of times.
Good luck and I hope it helps.
