Go to http://www.microsoft.com an dhunt down the File Format Converter for MS Word, download and install it and you might get the required result. It's actually to make files created in the 2007 and 2010 versions viable in earlier versions but it might help you as well.
Really silly question warning! Do you actually have MS Word installed in your Windows 7 installation? If not and if you don't want to pay for one, go to http://www.openoffice.org and download Apache Open Office 3. It has all the functionality of teh MS version but is free.