Hi Everybody, I am back after a break to sort out what I have learned. Unfortunately I got a Trojan Virus on my computer and, just to be on the safe side, had to restore my system to its factory settings and reload everything which took ages. As for my original problem, I think I made a fuss about nothing as I changed the TV ratio to 4: 3 and my new presentation works fine. I have given up on understanding non-square pixels for the moment as I want to push on and make some more presentations. By the way I posted a slidewhow on Beechbrook Cottage. How brave is that? Anyway, thanks for all your help. djay