You can export you OE mailbox as a .pst file which you can import into Outlook on your new machine (file-export-messages). I'm not sure whether it is possible to import a .pst into OE. Alternatively find the database files (search for *.mdb) and copy the relevant files (inbox.mdb, outbox.mdb etc etc). These files are stored in a funny place in Windows so be sure to paste them back into the correct location. Your contacts are stored as a .wab file so search for *.wab then copy it.