Here is what I found by using Help.
Question: How can I minimize the ribbon in Microsoft Word 2007? / I hid the ribbon but now I want it back. How do I do this?
Answer: You can minimize the ribbon is Microsoft Word 2007 by doing the following:
1) Open Microsoft Word 2007. At the very top of the window, click on the little arrow pointing down. (The arrow is next to the default shortcuts on the right of the Office Menu button)
2) In the drop down menu, click ‘Minimize the Ribbon’.
You can make the ribbon appear again, perform step no.1 and then unselect ‘Minimize the Ribbon’ by clicking on it in the drop down menu. The ribbon should appear.