Where can i get all my old outlook emails?

i;m planning to recover my lappy but i need to get all my old emails before i erase everthing. how can i do that. i can't find my old emails anywhere. can someone help me?

danke schon

Outlook or Outlook Express?

For Outlook have a search for *.pst; *.ost files

For Outlook Express you will need to search for *.dbx; *.wab