Configuring msn and windows 2000

I have a stand-alone computer with an up-to-date windows 2000 proffesional and the latest version of MSN Messenger.If I log-in with administrator rights I can run MSN messenger, everything works fine.. But when I log in as a user I can’t start the program. After I click on the progam, the cursor briefly changes to a hourglass and that is al that is happening. So I tried the run-as command and ran it as administrator. Again everything works fine. Because of security issues I rather run MSN Messanger as user. How can I do that??