Quick tip. I took a call from a developer today who had removed the .NET Framework 4.5 feature from a Windows Server 2012 development box. After a reboot only a command prompt was visible. When running SConfig there was no option to enable the GUI, PowerShell also wouldn’t fire up.
In this case to get your GUI back run the below from the command line :
Dism /online /enable-feature /all /featurename:Server-Gui-Mgmt /featurename:Server-Gui-Shell /featurename:ServerCore-FullServer