Users of Microsoft PowerPoint 2007 and later versions may view presentation files in PPSX format. Presentations saved in this format may be viewed, but may not be edited. To edit the presentation, you need to convert the file to another format that allows editing, such as .ppt. If you have a PowerPoint version earlier than 2007, download and install the Microsoft Office Compatibility Pack to enable you to open, edit and save presentations that were created in the newer versions of PowerPoint.
Open your PPSX file in PowerPoint.
Click "File" and select "Save As."
Click on the drop-down menu for "Save as type" and select "PowerPoint 97-2003 Presentation (*.ppt)."
- Microsoft: Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint File Formats