AutoCorrect and AutoText in Word 2007
It's important to distinguish AutoText from AutoCorrect. AutoCorrect kicks in when you've finished with typing something (as evidenced by typing a space, a period, or other punctuation). AutoText entries appear in a tooltip while you're typing; pressing Enter accepts the suggested completion. So, for example, typing four characters of your name and then hitting Enter would prompt AutoText to insert the whole name.
The problem is that in Word 2007, what was AutoText applies only to dates—type "wedn" or "febr" and you'll see it. According to Microsoft, the new Building Blocks feature takes over this function for other types of text. (To see this feature, click the Insert tab in the Ribbon, click Quick Parts in the text pane, and click Building Block Organizer. )
Clearly, Microsoft wants you to use AutoCorrect instead of the now-missing AutoText. The first challenge is simply finding the AutoCorrect options. Click the round Office button at the top left and click the Word Options button at the bottom of the resulting window. Now click Proofing in the list at left and click the Auto Correct Options button. Create an AutoCorrect entry to replace the first four letters of your name with your entire name. You'll have to remember to type a space afterward instead pressing Enter as you had in the past. But it will do the job.