To use the AutoCorrect feature as you type text in Word 2007, the "Replace
text as you type" option must be enabled. To enable the option, follow these
steps:
Click the Microsoft Office Button, and then click Word Options.
Click Proofing.
Click AutoCorrect Options.
On the AutoCorrect tab, click to select the Replace text as you type check
box.
Click OK to close the AutoCorrect Options dialog box.
Click OK to close the Word Options dialog box.