Here's two ways:
Go to Tools | Customize | Options and there should be a button for Reset
toolbars and menus. this will eliminate any buttons you may have added,
though.
--or--
Tools | Customize | Commands.
In the left column, click on Format.
In the right column, scroll down until you see Bullets and Numbering (NOT
the choices that only have one of the two words).
Drag the Bullets and NUmbering button to the Format Menu.
When the menu opens, place where you want it.
This method will not change any buttons you may have added.
tj