"C:\Program Files\Microsoft Office\Office\winword.exe" /unregserver The quotes are necessary, but you may need to change the path so it reflects the location of the winword.exe file on your system. (You can use Windows' Search tool to locate the path to the winword.exe file.) The /unregserver switch "unhooks" all the references to Word in the Windows Registry. You should then, immediately, use the following command: "C:\Program Files\Microsoft Office\Office\winword.exe" /regserver This command causes Word to rewrite all its Registry keys and to reassociate itself with document and template files. Now you can double-click a document file and see if Windows starts Word and opens the document.
Note: See TracWiki for help on using the wiki.