I think you can export your address book to a file......save it to disk, and then import it back in.
From outlook express help:
To export your address book contacts to other programs
You can export your address book contacts to other Windows Address Book files (WAB), as well as to Microsoft Exchange Personal Address Book, or any text (CSV) file.
To export your address book files to another Windows Address Book:
In Address Book, click the File menu, point to Export, and then click Address Book (WAB).
Locate and select the Windows Address Book file you want to export to, and then click Open.
For all other address book formats:
In the Address Book, click the File menu, point to Export, and then click Other Address Book.
Click the address book or file type you want to export to, and then click Export.
To import:
To import an address book from another program
You can import address book contacts from other Windows Address Book files (WAB), as well as from Netscape Communicator, Microsoft Exchange Personal Address Book, or any text (CSV) file.
For Windows Address Book files:
In Address Book, click the File menu, point to Import, and then click Address Book (WAB).
Locate and select the address book you want to import, and then click Open.
For all other address book formats:
In the Address Book, click the File menu, point to Import, and then click Other Address Book.
Click the address book or file type you want to import, and then click Import.
If your address book is not listed, you can export it to either a text (CSV) file or an LDIF (LDAP Directory Interchange Format) file, and then import it using that file type.