Exchange admins who have installed Exchange 2010 using the command line will be familiar with the Setup.Com, which was part of the 2010 ISO/DVD. It doesn’t exist in Exchange 2013!
In Exchange 2010, we used setup.exe to install the product using the GUI and Setup.Com to install it from a command line.
So, how are we supposed to run the setup from command line in 2013? I can hear you asking . Well, the answer is really simple. In Exchange 2013, the setup.exe is used for both purposes – installing from the command line and using the GUI. There is no setup.com file in 2013.
--> Please see the rest on the blog : http://www.howexchangeworks.com/2012/09/no-more-setup-com-in-exchange-2013.html