This may sound silly, but you aren't opening Word by inadvertently opening your saved document again, are you?
Unless Word has crashed badly, and its document recover system has been activated, you shouldn't be seeing a previous piece of work every time you open it (and even then, you should only see it as file to open within the program, it shouldn't automatically open the document for you).
If you are using a desktop shortcut to open Word, try opening it from the Start menu, if it opens as it should, just create a new shortcut and delete the old one.