You can set a PowerPoint slide as your Windows desktop background by exporting it in the JPG image format and installing it using Windows Explorer and the Windows Desktop Background command.
Open the PowerPoint presentation that contains the slide you wish to set as your desktop background. Alternatively, create a new presentation by loading one of the built-in templates.
Click the slide you wish to export to select it.
Open the Info screen by clicking File in the Ribbon. Select Save As to open a new screen.
Select either OneDrive or Computer, depending on whether you wish to save the image file on your OneDrive or on your local hard drive. Click Browse to select a folder.
Select JPEG File Interchange Format from the Save as Type drop-down menu and click the Save button.
Click the Just This One button in the confirmation box to only export the selected slide. Alternatively, click All Slides to export the entire presentation as multiple image files.
Launch Windows Explorer and open the folder that contains the exported slide. Right-click the image file and select Set as Desktop Background from the contextual menu.