Run this command from an elevated command prompt:
DISM /online /Set-Edition:ServerStandard /ProductKey:xxxxxxxxxxxxxxx /AcceptEula


DISM /online /Set-Edition:ServerDatacenter /ProductKey:xxxxxxxxxxxxxxx /AcceptEula

(Use key from table below)

Operating system edition

Product Key

Windows Server 2012 Datacenter


Windows Server 2012 Standard


The Edition ID will be ServerStandard, Or ServerDatacenter, and then insert the generic code. The server will run through the image conversion process, then restart twice.

After the server has restarted, you will need to re-activate the server. Go to settings > activation > change product key, and enter the code you purchased from us.

Note: It may take some time for the command to complete.

Purchase the license in the below website