PowerPoint File Types
PowerPoint uses three main file types: Presentation, Template, and Slide Show. For the most part, you can construct and deliver simple presentations without ever having to deal with the differences among these types of files. But before you can effectively use PowerPoint's advanced formatting options, you have to understand its file formats.
The Office XP Setup program registers a collection of PowerPoint file types. When you view the list of registered file types in Windows Explorer, you'll see the three major types listed in Table 30.1 (there are also some variant HTML file types which work much the same as these).
| File Type | File Extension | Default Action |
|---|---|---|
| PowerPoint Presentation | *.ppt | Open |
| PowerPoint Template | *.pot | New |
| PowerPoint Slide Show | *.pps | Show |
Thus, from an Explorer window, if you double-click an icon whose file type is Presentation (.ppt), PowerPoint opens the file for editing. When you double-click an icon whose file type is Template (.pot), however, PowerPoint creates a new presentation, based on the template, and takes you to the first slide so you can begin editing. Finally, if you launch an icon whose type is Slide Show (.pps), PowerPoint runs the show without ever showing you any of its slide-editing tools.
Surprisingly, the internal structure of all three file formats is exactly the same: You can save any presentation as a Template or Slide Show file, and the contents of the file remain the same.
Note
You will find many inconsistent references to these three file types scattered throughout PowerPoint's Help files and dialog boxes. In this book, the three terms defined in this section are used—Presentation, Template, and Slide Show—to differentiate among the three file types.
When should you use each file type? Follow these general guidelines:
Use the Presentation file type (.ppt) when you plan to edit the presentation and/or work with its design. To save a file as file type Presentation, choose Presentation in the Files of Type box in the Save As dialog box.
Use the Template file type (.pot) when you create a presentation that you want to use as the basis for creating new presentations, or if you will "borrow" the presentation's design for use in other presentations. To save a file as a Template, choose Design Template in the Save As dialog box.
Use the Slide Show file type (.pps) for presentations that you no longer need to edit or design. (Although it's possible to open this type of file from within PowerPoint, this is not the default action when you double-click its icon on the desktop or in an Explorer window.) Choose this file type if you want to be able to start a slide show directly from the desktop, or if you want a coworker to be able to double-click a file icon and see the show. To save a file as a Slide Show, choose PowerPoint Show in the Save As dialog box.
Tip from 
Because all three file types are internally identical, it's easy to change file types. Just choose a different format from the Save As dialog box. If you're comfortable working with file extensions in an Explorer window or at a command prompt, you can change a file type by changing the file's extension; for example, changing the file extension from .ppt to .pps converts a Presentation into a Slide Show.