W2K Prof – outlook98 -default manager

I installed outlook98 (corporate/workgroup) on a W2K professional PC. I did not make a user acct.on the PC, but did make a domain acct for the user. When the user logged in and was going through the setup of Outlook98 they got the Window asking about Outlook being their default manager. Clicked on YES. Every time Outlook is opened the samr window comes up. In control panel – Internet Options – Program tab – Outlook Express is in most of the fields. When I change them to Microsoft Outlook they don’t hold. Seems to be a permissions issue. How is it corrected? For all users with administrator rights on the domain there is no problem.