Office+2007+File+Format+Compatability

Microsoft has added new file formats to Microsoft Office Word, Excel, and PowerPoint 2007 to reduce file size, improve security and reliability, and enhance integration with external sources. To help ensure that you can exchange documents between Microsoft Office releases, Microsoft has developed a Compatibility Pack for the Office Word, Office Excel, and Office PowerPoint 2007 File Formats.

//**Open, Edit, Save, Create:**// By installing the Compatibility Pack along side of Microsoft Office XP, or Office 2003, you will be able open, edit, save, and create files using the Open XML Formats new to the 2007 Microsoft Office system.

Office 2000 users, as well as users of Windows 2000 SP4 and later, can convert Open XML Formats to binary file formats from within Windows Explorer. --- this is not done in the application, but in the operation system.
 * Convert file to old version--versions of office older than Office XP:**

[|Compatability Pack]: http://office.microsoft.com/en-us/products/HA101686761033.aspx