How do I open .docx files ?
1) 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) 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.
Windows users could also download the Word Viewer application from Microsoft that opens .docx documents properly but cannot alter them.
Last but not least it is possible to use the OpenOffice. OpenXML Translator to open docx documents if you have the Novell version of Open Office installed. I did not test it with the normal Open Office application, if someone did please mention if it succeeded in the comments.