I have always had people ask, “how can I import the auto-fill email addresses in Outlook?” Usually, this question arises after the previous installation is gone, and the only backup is a PST file. 

Microsoft offers this solution:

1. On the computer with the saved AutoComplete names, go to drive:\Documents and Settings\user name\Application Data\Microsoft\Outlook.
2. Right-click profile name.nk2, and then click Copy.

    

   Tip  You can copy the file to removable media, such as a floppy disk or a CD, and then copy the file to the correct location on the other computer. Or you can attach the file to an e-mail message and send the message to yourself. On the new computer, open the attachment in Outlook, and then save it to the correct location.

    

3. On the computer where you want to populate the AutoComplete feature, copy the file to drive:\Documents and Settings\user name\Application Data\Microsoft\Outlook.
4. If the Outlook user profile name is different on the computer where you are moving the .nk2 file, you must rename the file with the same Outlook user profile name after you copy it to the correct folder. For example, if you move Kim Akers.nk2 from the original computer with an Outlook user profile name of Kim Akers, and you copy the Kim Akers.nk2 file to the new computer, you must rename it with the Outlook profile name being used on the new computer.
5. When prompted about replacing the existing file, click Yes.
6. Open Outlook to view changes