“Businesses wanting to deploy standard configurations across a number of machines frequently take out one of Microsoft’s volume licensing programs, set up their own standard distribution then use it to hose whatever OS the PCs they bought came with. Frequently they are under the impression that this involves them paying for two Microsoft operating systems, and sometimes they’ll buy (if they can) machines with no OS instead, in order to avoid wasting money in this way….”
Link: theregister.co.uk