The file you need to look for is your Personal Folders file (*.pst) It's
where all the mail, calendar, contacts etc are stored.
Take a look at these pages for info on Outlook data backup:
http://www.slipstick.com/config/backup.htm
http://www.howto-outlook.com/Howto/backupandrestore.htm

Signature
Russ Valentine
[MVP-Outlook]
> Due to a 'malfunction' I had to reinstall Windows 98 (Dell) and all of my
> programs. I can access all my old data files for every program except
> Outlook. Any suggestions?