I was making a presentation in PowerPoint 2007 sp1. Yes it does matter what service pack you have, I encountered that animations done in sp1 did not work the same in PowerPoint without the service pack. The long story short, some sound files were not played completely during the slide show, even though preview did play them completely. After changing actual files with audacity (trying to make the sound files play correctly), I realized that if the files are not embedded in the presentation they are played just fine. I know there is sp2, but I did not want to update to it before my presentation is over. And in general, OpenOffice is waiting for my next presentation.