How to activate Windows Server 2012 Standard R2 Evaluation to Windows Server 2012 Standard R2 full version

I have installed Windows Server 2012 Standard R2 Evaluation from *.iso file downloaded from microsoft website in Hyper-V virtual machine.

The following step by step guide provides the activating to full version.

Even if we activate the windows using Server Key, by adding it from  My Computer --> Properties --> Change Product Key, it won't be activated. It will give the following error - "That key can't be used to activate this edition of Windows. Please try a different key"

Two ways to verify that our product is evaluation:

1. The evaluation notice can been seen at bottom right corner of  desktop background.
   
2. From an elevated command prompt do the following:
• Determine the current edition name with the command 
• DISM /online /Get-CurrentEdition.

               It will show  "Current Edition :  WindowsServerStandardEval"


To convert to full version follow these steps:

In elevated command prompt (Open command prompt using Run As Administrator) the following commands

System 32> dism /online /set-edition:serverStandard /productkey:<YOUR KEY> /acceptEULA

Example:

System 32> dism /online /set-edition:serverStandard /productkey:XXXX-XXXX-XXXXX-XXXXX-XXXXX /acceptEULA


The server will execute some scripts and then it will be converted to full version.

It will ask for a server reboot. Enter "Yes" then server will be rebooted and upgraded to full version.

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But, sometimes, the version won't be activated in "Windows Properties" windows.

For that,   Go to  "Change product key" --> Enter the valid license --> Now it will be activated (Internet connection should be there)

Then the Windows Server is activated.