I've posted this in a couple of other places but thought I'd post in a less obscure place since several folks seem to have had this problem.  Specifically, once SP2 is installed, all old Outlook Express messages and addresses seem to have disappeared.  What apparently happens is that SP2 creates a new identity called 'Main Identity (**Backup**)', and when you open OE that's the identity that comes up.  To get stuff back - go to the File menu, choose 'Switch Identity', and then choose 'Main Identity' without the **Backup** notation.  That should bring up your old data.  Don't know if this will always work but has for me and several others.

Lee