Have you accidentally turned off the ability to indent your bullets with tab and shift-tab? I did. And it was a very obscure solution to turn it back on. Here is the Word 2007 version to turn it back on (or off, if you’re having troubles getting the formatting just right). The Office Button is where you open/save/print files and find other Word options.
Office Button | Word Options | AutoCorrect Options | AutoFormat As You Type: “Set left- and first-indent with tabs and backspaces