It is possible to compare two or more PowerPoint Presentations by viewing them side by side on screen at the same time. This can be helpful if you have two versions of the same presentation and need to make a final check or you want to compare a previous year’s information with the current year's.
1. Open the PowerPoint files that needed to be compared.
2. On the "View" tab, click on the "Arrange All."
These instructions, along with illustrations and instructions for additional features of Conditional Formatting for Message Lists, can also be found in SharePoint > Software Users Group > Shared Documents > PowerPoint > View Two PowerPoint Presentations at the Same Time.