Enable Remote Desktop on Windows 2008 Server Core

Logon and use the following commands:

Cscript %windir%\system32\SCRegEdit.wsf /ar 0
Enable remote administration from Windows Vista/Windows 2008/Windows 2008 R2 and Windows 7

Cscript %windir%\system32\SCRegEdit.wsf /cs 0
Enable remote administration from legacy operating system