I have the same issue. I created the slides in ppt 07 and saved as 07 and 03
version. Send the slides to someone using 03 and they cannot get the slide
show to run - slides do not advance. I have checked the multiple monitor
option and it is grayed out but set to primary. I am using 07 on 2 diff
machines and the slide show runs on both of my machines but not on anyone
using a lower version - despite saving the slides for a lower version