In order to open a PPS file, PowerPoint must be installed on the machine you're trying to open the file on. If the machine isn't equipped with PowerPoint or has an earlier version of PowerPoint, you'll receive an error message if you try to open the presentation show. If you need to run the show on a machine that doesn't have PowerPoint, you can use the PowerPoint Viewer 97 (for PowerPoint 97), the PowerPoint 2000 Viewer 97 (for PowerPoint 2000), or the PowerPoint Viewer 98 (for PowerPoint 98 on the Mac). You can download the Microsoft PowerPoint Viewer from Microsoft's Web site. If you're running PowerPoint for Windows, go to
http://office.microsoft.com/downloads/9798/Ppview97.aspx
You can download both the PowerPoint Viewer 97 and the PowerPoint 2000 Viewer 97 from the same location. If you're using PowerPoint 98 for the Mac, go to
http://support.microsoft.com/support/kb/articles/Q190/9/86.asp Here you'll find information on downloading and installing the PowerPoint Viewer 98.