Windows KMS

To install a new KMS host key for Windows 8 activation or for Windows Server 2012 activation, run the following command:
cscript %windir%\system32\slmgr.vbs /ipk
Note In this command, "KMS host key" is a placeholder for the new KMS host key for Windows 8 activation or for Windows Server 2012 activation.

Important Every KMS host key is associated with a group of Windows editions. Additionally, a KMS host key that is associated with Windows client operating systems cannot be installed on Windows server operating systems, and vice-versa. This is true for all Windows operating systems except for Windows Server 2003.