These are words you probably don't want to hear. Use
Mozilla Thunderbird email client and
Mozbackup to backup this and Firefox (all free).
Simple as. Works a treat saved my bacon more than once.
But if you must stay with Outlook express, then, use
this guide. There are commercial one click backup programs for OE but why pay.
If you want a one click free backup solution then Thunderbird and Mozbackup are the go.