we have two email accounts and seperate users on our computer how can we set up outlook express so that our emails come down to are seperate accounts when we click on send/receive

At present i receive emails to both accounts even thou my email address is not present on my wife user account

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Logon to your wife's (windows)account ,Start Outlook
Go- Tools>Accounts>Mail tab , highlight any accounts listed there and remove them.
Shut off Outlook and restart it .(If they don't go away Just make your wife's new account the defaut account and on each of the unwanted account Uncheck the "Include this account when receiving or syn..." at the bottom of the property page for each one.
You will need her email address,incoming and outgoing mail servers and the password for her account, authentification and SSL (your ISP will tell you if you need it)
Go back to the mail page above click add and just input the info in the appropriate boxes.