Second Level Address Translation
If like me, you are running the Enterprise Evaluation edition of Server 2012, on an older server, because that is what you have available for the evaluation, You may find that it does not support virtualization. You will get a pop-up with a couple of big red Xs and the message "Hyper-V cannot be installed: The processor does not have the required virtualization capabilities".
It's worth checking the BIOS to see if there are any virtualzation attributes that you can enable, but most likely, you will have to go on line and find out which processors support Second Level Address Translation, and either get a Server that has a compatible processor, or forget about evaluating Hyper-V.
