Removing outlook express

We do not encourage the use of outlook express on our network. How do I remove it from the PC. I have tried to delete and rename msimn.exe, but windows recreates it. I have tried to uninstall the component in the add/remove programs to no avail. I have tried to restrict its use in add/remove programs. But the moment I click on the msimn.exe file, outlook express starts. Any ideas?