If you want to turn a Server 2012 (or Server 2008 R2) into a workstation machine and have it behave like Windows 8 (including the ability to burn ISO files from within File Explorer, and personalizing your desktop wallpapers and other settings), all you need to do is add the DesktopExperience feature. This is how you'd do it with PowerShell:
Add-WindowsFeature -Name Desktop-Experience
In PowerShell 2.0, you first have to import the appropriate module manually:
Import-Module ServerManager
