outlook express

Outlook Express stores your messages in .dbx files.
There is 1 .dbx file for each OE folder plus 1 more.

The location of the dbx files depends on the version of OE and Windows that you are running.

For Windows 2000 and XP, the files should be at:
C:\Documents and Settings\{User Name}\Application Data\Microsoft\Outlook Express

For W98, the path is along the lines of:
C:\Windows\Application Data\{a string}\Microsoft\Outlook Express
There will be a separate string and related set of folders for each user.

Similarly, you should backup your address book.
It will be in the address book folder.

An easy way to backup OE mail is to use OE Backup from:

http://www.oehelp.com/OEBackup/Default.aspx

Chas