Microsoft has released Compatibility Pack 4 for Microsoft Office. What’s this mean? If you are running an older version of Office (2000, 2003, XP), and you try to open a newer XML based 2007 or 2010 document (.docx, .xlsx, etc.), it will give you an error. With this pack, you will be able to open the newer documents.
By installing the Compatibility Pack in addition to Microsoft Office 2000, Office XP, or Office 2003, you will be able to open, edit, and save files using the file formats in newer versions of Word, Excel, and PowerPoint . The Compatibility Pack can also be used in conjunction with the Microsoft Office Word Viewer 2003, Excel Viewer 2003, and PowerPoint Viewer 2003 to view files saved in these new formats. For more information about the Compatibility Pack, see 924074.