If you are a regular user of Microsoft PowerPoint for a long time, you must be aware of the PPT and PPTX file formats. Both these presentation file types have been part of Microsoft PowerPoint for quite some time now. PPT is the oldest PowerPoint file format that had been widely used for saving presentations to disc. It was replaced by the newer PPTX file format with the introduction of Office 2007 which is the default format for saving presentations ever since.