Please help!

Following an upgrade of my microsoft office from 2007 to 2010 the word templates/styles arent working properly. Clicking on Normal, title and Subtitle work fine - but heading 1 and Heading 2 are not working at all.
I just click on "heading 1" when the text is highlighted and the text just stays at or returns to "normal".

None of the templates are working properly!

Thank so much