A: If you have already installed Windows Server 2012 Standard, it's actually very easy to move to Datacenter provided you have a Datacenter key. At a command prompt, type the following and click Y when prompted (the machine will actually reboot twice, and after rebooting will be Datacenter). This process also works on Windows 2008 R2: <code><strong>dism /online /set-edition:ServerDatacenter /productkey:<Datacenter key, e.g. AAAAA-BBBBB-CCCCC-DDDDD-EEEEE> /AcceptEula</strong></code>

dismchangeversionsml
DISM TOOL

Note: You can't just type in a Datacenter key in the Windows Activation control panel dialog box to upgrade--you will receive an error.

You can always check your current version, and the versions you can upgrade to, by using DISM as shown below:

<code><strong>dism /online /get-currentedition</strong></code> <code><strong>dism /online /get-targeteditions</strong></code>

This server can't be a domain controller (DC) and would need to be demoted prior to perform the version upgrade using DISM. See also, "Q. Can I upgrade to Windows Server 2012 Standard from Windows Server 2008 Datacenter or Windows Server 2008 R2 Datacenter?"