Viewing ppt issues - seeing right half of 2 pages

I installed impress on a new windows 8 laptop. I have a number of ppt slides which I can edit in impress but when I try and run them the a ppt slideshow which I can edit in impress. When I try and run with default settings I get 2 slides side by side horizontally, but it only shows the right hand half of each screen.

Any ideas how I can run the slideshows?