Microsoft Word is the word processor tool included with Microsoft Office. If you just need to view or print the document, we recommend using the Word Viewer. If you need to edit or modify the document, you will need to use OpenOffice.
DOCX Word Documents are different than the DOC version in that they use the Microsoft Office Open XML format. The Open XML format makes it easy for other programs, such as OpenOffice.org, to read DOCX files (and other Open XML file types). The Open XML format was introduced with Microsoft Office 2007.