Hi,
Windows Server 2003 SP1 is a very good security update released by Microsoft and I hope many of you would have already installed the same.
However, if for some reason, you had to remove the SP1 then you may no longer be able to browse ASPX Pages.
This article http://harishmvp.blogspot.com/2005/05/unable-to-browse-aspx-pages-on-windows.html explains the resolution for the same.
Thanks.
regards,
Harish
http://geekswithblogs.net/ranganh