When you say you have tried editing your existing file, is this the procedure:
1.On the File menu, click Open, and then navigate to C:\Documents and Settings\user name\Application Data\Microsoft\Templates.
2.Double-click the Normal.dot file to open it.
To be certain that you're working in the default template, check to see that Normal.dot appears in the Word title bar.
3.Make any changes you want, using the menus and dialog boxes just as you would to change default settings for a document.
4.When you have finished, on the Standard toolbar, click Save.
I have found this link helpful:
Microsoft Office Word 2003http://support.microsoft.com/ph/2530