When I worked on a large contract for a customer with 20,000 desktops and a couple of thousand servers we used to take great delight in waxing about our server virtualisation to major hardware vendors... and then drop the bomb that we had virtualised 250 instances of Windows NT...
NT was (then) 7 years out of support and is nearer 10 now. But if you have apps that run on it, they still run on it...
However trying getting an replacement network card with NT drivers these days. Virtualisation is your man...