How to Back Up the Windows Address Book
Copy the .wab file to another folder. If you copy the .wab file to another folder, you do not need to change the file name:
1. Quit Outlook Express.
2. Create a new folder to store the .wab file in. For example:
C:\Backup
For information about how to create a folder, click Start, click Help, click the Index tab, type new folder, and then double-click the New Folders topic.

NOTE: You do not have to create a new folder; you can use a folder that already exists.
3. Locate the .wab file. To do so, click Start, point to Find, and then click Files Or Folders.
4. In the Named box, type *.wab, and then click Find Now.
5. Copy the username.wab file to the folder that you created in step 2, where username is the name or alias of the Outlook Express user that the .wab file belongs to.