Enabling Active Directory Users and Computers in Windows 7
I had to download the update mentioned: http://www.microsoft.com/downloads/details.aspx?FamilyID=7d2f6ad7-656b-4313-a005-4e344e43997d&displaylang=en
Then I had to run these command lines as an administrator:
dism /online /enable-feature /featurename:RemoteServerAdministrationTools dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS-SnapIns