If you do not have PowerPoint installed on your computer, you can still open and view PowerPoint presentations by using PowerPoint Viewer, PowerPoint Mobile, or PowerPoint Online.
PowerPoint Viewer is a free download from Microsoft.com. (It was created in conjunction with PowerPoint 2010, but it can also be used to view newer presentations created in PowerPoint 2013 and PowerPoint 2016. However, if a presentation uses a PowerPoint feature, such as an animation) introduced after version 2010, that feature can't be shown by PowerPoint Viewer.)
You can open, view and print presentations using PowerPoint Viewer, but you cannot edit them. All transitions, videos and effects appear and behave the same when viewed using PowerPoint Viewer as they do when viewed in PowerPoint 2010.
PowerPoint Viewer supports opening and viewing presentations created in PowerPoint 97 and later versions. It views files that have any of these filename extensions: .ppt, .pptx, .pptm, .pot, .potx, .potm, .pps, .ppsx and .ppsm.
PowerPoint Viewer opens supported presentation file types only if a version of PowerPoint is not installed on the PC that is being used. If PowerPoint is installed, it opens the presentation and PowerPoint Viewer is not used.
To install PowerPoint Viewer, download it for free from the Microsoft Download Center, and follow installation instructions on the download page.
Other ways to view presentations
Microsoft has two free alternatives that provide some of the same benefits of PowerPoint Viewer and that can display some new PowerPoint 2013 and PowerPoint 2016 features (such as the Morph feature and animations added to PowerPoint after version 2010):
PowerPoint Mobile If you are using Windows 10, PowerPoint Mobile is installed on your system. It is a slimmed-down version of PowerPoint in which you can view and edit .pptx and .ppt files. To find PowerPoint Mobile on your computer system, go to the Cortana Ask me anything search box next to the Windows Start button on your computer desktop, and type the name PowerPoint Mobile.
PowerPoint Online If you have a Microsoft account (hotmail.com, live.com, msn.com) or an Office 365 work or school account, you can view and edit presentations for free in a web browser by using PowerPoint Online.