If this has ever happened to you, you will certainly be interested in NW Docx Converter, a free program to convert the format of these types of files to the standard .RTF, which doesn't need one of the above programs to be installed.
NW Docx Converter supports the conversion of the following formats: .DOCX, .DOTX (Microsoft Office), .SXW, .ODT (OpenOffice), .PDB and .PRC (Palm Office), and in addition to saving them in .RTF it allows you to export them as a .PDF or .XML file. It also allows the abovementioned formats to be associated to the program. Something very useful is you don't have Word or Writter installed and you're not thinking of installing it in a short term.
Finally, the conversion options allow you to adjust the size of the document, converting only a certain number of the total pages or printing any of the pages in grayscale.