The Microsoft Word have multiple version, each time the newer version in launched it contain rich features which may be possible not available in the previous versions. If you have observed whenever a word 97-2003 document is open in MS Word 2007 it shows compatibility mode in the title bar which means it disable the new features. In order to use the new features you have convert the 97-2003 document into MS Word 2007 format.
This tutorials teach you the way to convert the word 97-2003 document into MS word 2007 format to use the complete features.
Open the Word 97-2003 Document in Word 2007
As you can see in the title bar the word document is opens in compatibility mode
Click the office button
After that Click the convert button from office menu
Word exits the compatibility mode