Cannot use Open in New Window option but works for Administrator

I am having a problem with Internet Explorer 6 SP1 installed on a computer
running Windows 2000 Professional with SP4. Everything was working fine
until about a month ago and it just stopped working.

When a user logs on to the computer, they cannot use the "Open in New
Window" feature when clicking on a hyperlink. When they do so, nothing
happens. Also if they click on a link in any other application (i.e.
Outlook) or a link in the web browser that launches a new window, it doesn't
work. However, if I give this user administrator rights on the computer,
everything works fine.

I found a knowledgebase article from Microsoft, article number 281679, which
discusses using regsvr32 to register a long list of dll's and checking some
registry keys and I performed all of these steps but nothing worked.

Please help.

-Tim Nichols