Upgrading win98 to win 2000

I was upgrading three of my corporate machines from windows 98 to windows 2000. One of machine got stuck half way when installing network software allowing it to connect to other computers, networks and internet. I was advised to restore the full sytem. But before I do that, I want to locate all e-mails and make a back-up of them as I did to the other data. Currently I am working under DOS environment which doesn’t allow me to export or import any mail messages. Can you assist me.