Windows 7 Tip: 
Most of the some of us received a DOCX file which cannot be opened directly by Microsoft Office 2003 or earlier versions? DOCX file is generated by MS Office 2007, which is totally different from previous versions, thus opening DOCX files can be an annoying task. So am here posting the 6 ways which will help you to open the docs files quickly and easily.
1. Microsoft compatibility pack – The best way for Windows users who have a version of Microsoft Office installed is to install the Microsoft compatibility pack for previous Office versions that adds .docx support in Microsoft Word.
2. Open XML Translator – Open XML Translator, which is a versatile for us to open, view and edit DOCX files with ease.
3. Word Viewer application 2007 – Windows users could also download the Word Viewer application from Microsoft that opens .docx documents properly but cannot alter them.
4. Open XML File Format Converter for Mac - If you are a Mac User than Try Open XML File Format Converter for Mac offered by Microsoft, as this is a tool for older Office Mac users to open, edit and save a .docx file on Mac OS.
5. Docx2doc.com – The best approach for users that do not use Microsoft Office, including Mac and Linux users, would be to use one of the several online converters that convert docx files into doc.
6. Docx-converter.com - You can either browse the DOCX files and then let it convert, or you can also download the appropriate tool to help you. This site is free to convert.
7. Zamzar – This site only provides online conversion with free of charge. It cannot only help users to convert DOCX files, but also XLSX, or PPTX file formats.
Quite a list you have here, though I may not have any use since I already use Office 2007
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