In Word 97 and 2000, click on Tools | Options | Edit tab | check
the "Tabs and backspace set left indent" box | OK.
In Word 2002 and 2003, click on Tools | AutoCorrect Options |
AutoFormat As You Type tab | check the "Set left- and
first-indent with tabs and backspaces" box | OK.
In Word 2007, click on Office Button | Word Options | Proofing |
AutoCorrect Options | AutoFormat As You Type tab | check the "Set
left- and first-indent with tabs and backspaces" box | OK.