Unfortunately, you didn't tell us which operating system you're using or which Outlook Express version you have installed but...the link below provides good information from Microsoft about such backups:
How to back up and to restore Outlook Express data
Hope this helps.
Grif
Hi, I had a post last week about losing all of my outlook express email files, their gone but I don't want this to happen again if it does happen, what would be the easiest way for me to copy and backup these files say I have a file with all my ebay emails in OE, could I copy/save the whole file in outlook express to say my desk top or somewhere safe and easy to get to and keep adding important emails to it as I get them? thanks

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