To quickly open the Normal template as a document, you can use the following trick: In Word, press Alt+F11 to display the Visual Basic Editor. Press Ctrl+G to activate the Immediate window. Type
NormalTemplate.OpenAsDocument
and press Enter. Normal opens in a separate document window (look at the title bar). Close the Visual Basic Editor and change the defaults in Normal.
Note that most changes (such as changing font, size, line spacing, etc.) can be done from Word's dialog boxes, without opening Normal. If you find that you have to open the template for these changes, something is preventing you from correctly saving it. This
must be troubleshot separately; see the sections referring to add-ins in the KB article at
http://support.microsoft.com/kb/921541/en-us/.