Dude, Where's my GUI - Windows Server 2012/R2

During one of my classes, a student encountered an issue with his virtual machine (VM) which was running Windows Server 2012. After attempting multiple solutions to fix the issue the VM restarted but all that came up was the command prompt, the Server Manager tool didn’t start, there was no task bar. Holy crap, we just lost our GUI!

After doing some search to ensure this wasn’t a result of the issue that started this crusade, I did some research focusing on the lost GUI and found the ‘Holy Grail’ - a TechNet Server and Tools blog post explaining the cause and solution. We apparently removed .NET 4.5 while trying to resolve our issue and ended up losing the GUI. The saviour post is: Removing .NET Framework 4.5/4.5.1 removes Windows 2012/2012R2 UI and other features

And this articles explains different ways to add and remove the GUI: How to Turn the GUI Off and On in Windows Server 2012

The sad part is, I can't remember the main issue that cause this entire situation.