Either you have a bootleg of Windows Vista or somehow obtained IE7...which I thought was only being released with Vista. I just however learned you can download a beta edition of Internet Explorer 7 which features the ever impressive "tabs" feature.
Did someone build this for you? I didn't think DELL would release a beta edition with their builds.
http://www.microsoft.com/windows/ie/default.mspx
Anyhoo, I would suggest one of three things...
Uninstall IE7 and download it again form the link above.
-or-
Leave it and download FireFox and use that as your default browser, it has been running like IE7 for a couple years now.
http://www.mozilla.com/firefox/
-or-
Uninstall IE7 and install IE6 from the below link.
http://www.microsoft.com/windows/ie/...1/default.mspx
All three options will get you going and not cause any lasting errors.
Threaded Mode