You all must have faced this problem at least once, i.e. opening office 2007 files in older versions.
Actually there is new button (resembling windows button in looks) which you can click and save it as according to your preferences such as 97-2003 document which is compatible for older Office packages. But people does not recognize this button and save their document in default extensions

such as .pptx or .docx etc, which are not compatible in Office 2003 package.

But now you have one option through which you can open .pptx or .docx files in older office packages (Other than office 2007) also. Offcourse new office 2007 is smarter than previous versions but its not that much distributed. 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 new to Word, Excel, and PowerPoint 2007. 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. It's just around 28 MB file you have to download and install.
For downloading click :Compatibility Pack
Keep \m/ing

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