In the Server Manager browse to the Security Information section in the right hand pane and click 'Configure IE ESC'. IE ESC is located in the very lower right-hand corner of the window. In the Internet Explorer Enhanced Security Configuration window decide for whom you want IE ESC enabled or disabled and click OK.
In Windows Server 2003, you can turn off enhanced security for IE by going to Start, Control Panel, and then Add or Remove Programs. Next, click on Add/Remove Windows Components on the left hand side: Scroll down to Internet Explorer Enhanced Security Configuration and uncheck the box to turn it off.