I can't associate a .pps file with Microsoft 2007 Powerpoint Reader. "Control Panel, Default Programs, Associate a file type with a Program, select .pps" doesn't list the Reader even though I just re-installed it. If I open the Reader program and select a .pps file, it will open it so the file is good and the Reader works. I've tried the approach of right clicking the file, selecting 'Open With' (Rreader isn't listed), finding the file in Explorer and "selecting the Reader as the default program" (tunnelling down to Programs and selecting the Reader) but no luck.
These approaches have always worked on other Vista machines I support.