Product:
Cognos BI 8.4.1
Windows 2008 R2 Server

Symptom:
User get a error when they try to surf to Cognos connection using an old shortcut on the desktop.
It have worked the other day.

Error message:
404 – File or directory not found

Cause:
The IIS on Windows 2008 server is stopped to allow CGI.

This is simply done by inside Internet information services manager,
go to the server and click on “ISAPI and CGI Restrictions”
on the right side click on “Edit Feature Settings”
in the dialog Edit ISAPI and CGI Restrictions Settings
uncheck “Allow unspecified CGI modules”
and leave “Allow unspecified ISAPI modules” checked
click OK

This will stop all CGI access to the IIS server, if you not have explicit added exceptions in handler mappings.

Solution:
Ensure the user surf to http://servername/cognos8
instead of http://servername/cognos8/cgi-bin/cognos.cgi

Recommendation is to use cognosisapi.dll instead of cognos.cgi on Microsoft Windows server because they use less windows resources.