if you are using outlook express do a search for:-
you will need to set the search parameters to include system and hidden files
then copy this file to your new p/c desktop, right-click on the file - select properties and take the tick out of 'read only', then start outlook express mark the file as . start outlook express and clcik on the 'file' tab at the top / import / address book and point to the wab file on your desktop.
sorry if it sounds a bit fiddly but it is very straight forward. any problems please post back