If you don't have PowerPoint installed on your computer, you can still open and view PowerPoint presentations by using PowerPoint Online or a mobile app. PowerPoint Viewer has been retired.
A new way to view presentations
PowerPoint Online is a free alternative that provide some of the same benefits of PowerPoint Viewer and can display some newer features (such as the Morph feature and animations added to PowerPoint after version 2010).
If you have a Microsoft account (hotmail.com, outlook.com, live.com, msn.com) or an Office 365 work or school account, you can view and edit a presentation for free in a web browser by saving the file to OneDrive or Dropbox and using PowerPoint Online to open it.
PowerPoint mobile apps
Office mobile apps allow you to open Office documents on your device. For a list of download links for the Office mobile apps, see the table in Supported versions of the Office viewers.
PowerPoint Viewer was retired on April 30, 2018. It's no longer available for download.