All of your Outlook Express 5/6 mail folders and emails are stored in one directory, called the store root directory, which can be determined by selecting "Tools| Options| Maintenance| Store folder" in OE.
Under store root directory, you can find several .dbx file. The 'Folders.dbx' file is the master index of the entire store, which stores the tree structure of the mail folders and additional information. The 'Offline.dbx' file stores IMAP and Hotmail actions, if you have an IMAP or Hotmail account. The 'Pop3uidl.dbx' file keeps track of messages left on a POP3 mail server.
All remaining .dbx files correspond to Outlook Express folders with the same name. For example, Inbox.dbx corresponds to your inbox folder in OE and MyFolder.dbx corresponds to 'MyFolder' folder in OE. You can also find the full path of the dbx file corresponding to a OE folder by right-clicking that folder in OE and then clicking "Properties".
The actual emails of a Outlook Express folder are stored in its corresponding dbx file.
You might be able to make a copy of your existing dbx files and swap them out for the older ones but thats a little klunky.
you can also try this shareware program to read the old .dbx files
http://www.expressarchiver.com/
also
I use this program
http://www.abf-soft.com/
all the time. it will allow you to move outlook express COMPLETELY between different computers. It will also allow you to make a 1 file backup of outlook express with all settings and e-mails. It has saved me countless hours in the field and has saved more than 1 managers arse in a pinch.
hope this helped