For Win 2K:
-Press F3 or go to Find files.
-Type "outlook express".
-On the search results window, look for the longest directory of the Outlook Express folder(usually in C:\Documents and Settings\Your_Name\Local Settings\Application Data\Identities\Number_ID\Microsoft
-Make a copy the folder.
-On your new computer, use the Import function on Outlook Express and point it on the Outlook Express folder you've just copied.
Cheers,
Biggs