I recently purchased a few Lenovo TS140 servers with Windows Server 2012 R2 Standard licenses. I was expecting the licenses to be assigned via Microsoft’s eOpen Licensing Agreement, however, they were purchased from Lenovo as a Re-seller Options Kit (ROK). The real issue was that the Licenses were being shipped from Hong Kong to the US, which would delay my server install by a full week. The solution, Install Server 2012 R2 Trial and Activate Windows with a ROK key once it arrived. Note that ROK keys are locked to OEM devices and cannot be installed on other hardware.
Now I have a trial version of Server 2012 R2 and a ROK Key, the server would not take the key via traditional means. In order to Activate a Windows Server with a ROK key, we must issue the following command from the command line. Nte that this is for Server Standard Edition
[shell]DISM /online /Set-Edition:ServerStandard /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula[/shell]
And that’s how you Activate a Windows Server with a ROK key.
Original forum post from SpiceWorks