Transfer customizations in normal.dot from Word 2003 (and earlier) to new normal.dotm in Word 2007 

Customizations stored in normal.dot:  Formatted AutoCorrect entries, AutoText, keyboard shortcuts, menu customizations, custom toolbars, styles, macros. 

When you upgrade on the same computer, Word 2007 should use your existing normal.dot as a starting point for creating the new normal.dotm.

If Word 2003 (or earlier) is on a different computer, rename or delete the normal.dotm file that Word 2007 created.  Paste your old normal.dot file into the folder where Word 2007 stores normal.dotm, then start Word.  When Word doesn't see normal.dotm, it will use your old normal.dot to create a new normal.dotm. 

Back up your new normal.dotm!