The file was made in Microsoft Works, which is an all in one package containing a word processor, a spreadsheet and a database, all pretty simple. Word has a built-in converter for it, which may or may not have been installed when you installed Word.
You should be able to open it by opening Word first, then using the file open menu item. Select All Files in the Files Of Type dropdown box and navigate to your file. The converter should switch in automatically if it's there