I've downloaded an Arabic file and it's in Microsoft Office PowerPoint. When I try to open it, it says to download a new version of PowerPoint for the file to work.
You need to have Microsoft PowerPoint 2007 or upper in order to open certain file types. For example, PowerPoint 2003 uses PPT as a standard file type while PowerPoint 2007 uses PPTX. This is actually the problem you're experiencing. Install PowerPoint 2007 and it should work.