Microsoft PowerPoint Viewer
Microsoft PowerPoint Viewer is the last official version released by Microsoft. You can use it to view full-featured PowerPoint presentations.
PowerPoint Viewer registers with the .ppt, .pptx, .pptm, .pot, .potx, .potm, .pps, .ppsx and .ppsm file extensions only if a version of PowerPoint is not installed on your computer.
If registered, double-clicking on these file types will launch PowerPoint Viewer.