When a presentation is set up as a kiosk, PowerPoint adds a feature you may or may not know about. It automatically re-starts the presentation after five minutes of inactivity. This is good for unattended presentations, not so good for attended ones where there is a lot to read on a single slide.
Having said that, I also need to say in PowerPoint 2002 this feature is broken. The timer doesn't work. So, PowerPoint MVP Chirag Dalal, has created a free add-in to fix the broken timer in 2002: http:// officerone .tripod.com/kioskassist/kioskassist.html (there is no www in this address).
The feature was fixed in both PowerPoint 2003 and the 2003 Viewer, the add-in is only required with PowerPoint 2002.