I installed .net framework 4 on my windows 2003 enterprise x64, wrote simple asp.net 4.0 application (default.aspx page only). The application works great if request is to default.aspx, not to the root site: contoso.com/ - doesn't work (Get 404 error) contoso.com/default.aspx - works. Default.aspx is in list of default documents in IIS. Please help.