If you are still using Microsoft Word 2003 or Word 2000 then you need to have this tool which converts .docx file to .doc file. Microsoft Word 2013, 2010 and 2007 by default create document with .docx extension. Opening .docx using word 2000 or 2003 would display the following message that “This file was created by a newer version of Microsoft Word. Do you want to download a compatibility pack so that you can work with this file? ”
This can be resolved by downloading Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats from Microsoft site.
After downloading and clicking on the executable file, you will be prompted with the following dialog
Click on Run button to continue installation and accept the Microsoft Software License Terms to install the Compatibility Pack
After installing this, you would be able to open the converted word document but you might get the below warning message if word 2007 styles have been used.
Now you will not have any issues while opening the latest version of word documents (*.docx) in Word 2003 or Word 2000.