About file conversion in PowerPoint
Microsoft Office PowerPoint automatically opens Microsoft Office files, and many other types of files, in PowerPoint format. PowerPoint uses converters to convert files to the correct format. If PowerPoint recognizes the format of a file, it converts the file and opens it. Some converters are installed when you perform a Typical install. You can run Office Setup and add others if you need them.
If PowerPoint can't open the file you want, first open the file in the source program, and then save it in a file format that PowerPoint can open, such as Microsoft Word, Microsoft Excel, PowerPoint, Harvard Graphics, or Lotus Freelance; or, convert the file to a graphics or text format that can be opened in PowerPoint.