Outlook Express

A workmate recently uninstalled Internet Explorer 4.0 from a users PC in order to create space,this deleted Outlook Express.You do need Internet Explorer to be able to run Outlook Express.I reinstalled Internet Explorer 5.0 & Outlook Express,problemis,we can’t seem to retrieve old messages which he had backed up onto a different folder.We tried to copy them back into the Outlook folder,under identities,however the messages still won’t appear when you are in Outlook express.Please assist.