Marwa, I haven't watched that tutorial that you've linked, but I had created my own based on Server 2012 R2 (but will apply exactly on Server 2008 R2) as since 2008 R2, PHP was handled by FastCGI rather than CGI, all you have to do just spend 2 hours of your time and work around installing Moodle on Windows Server.
you can watch tutorial here
http://blog.academictools.org/2015/12/installing-moodle-on-microsoft-windows.html
also, before starting, preferably uninstall IIS so you can start fresh with options that are actually needed for running Moodle.