I have XP SP3. I have downloaded MS PowerPoint Viewer 2003. I cannot open PPS files, I have removed and reinstalled version 2007 twice from the Microsoft site and followed the procedure to associate a programme, then I changed to 2003 version, which I have as a saved download, and repeated the procedure to associate a programme, it will not work, but, if I save the file to the desktop it will open no problem, PowerPoint itself opens immediately and then the file opens. I had this problem a while ago but I have lost the solution from this forum. I have searched through all the threads on here and via Google, nothing works. When I download the viewer from Microsoft, 2007 version, it installs a folder named Microsoft Office 12! Talk about going round in the proverbial circles!!!