Stopping Server Manager from at Windows 2008 2012 Startup

Stop Server Manager from Automatically 

Launching in 2012 

Step 1- Go to Server Manager Properties (Top Right Corner)- 

Step -2 - Uncheck "Do not start Manager...."

Stop Server Manager from Automatically 

Launching in 2008

In Server Manager, under the Server Summary section, enable the checkbox beside Do not show me this console at logon as shown below -