Activating Windows Server 2008 Core
Server Core is a minimal server installation option for computers running on the Windows Server 2008 R2 operating system. Server Core provides a low-maintenance server environment with limited functionality. Command-line tools and other management tools (both local and remote) can be used to manage a machine running Server Core. For a list of command-line tools, see Command-line reference A-Z.
To activate your Windows Server 2008, you can login to the server console and type the following shell command and press Enter in the Windows shell:
cscript C:\windows\system32\slmgr.vbs -ato