Microsoft provided research to CERN, not OS.
CERN probably used Linux because it's highly customizable.
LOL. Playing adult games with baby toys? Sure you do not even begin to grasp the computational tasks that are to be done in order to make a 5 sigma discovery of such heavy particle. You probably have a desktop-level knowledge of OSes, dont you? you could check the numbers, like data flow, amount of storage, flops etc which are needed in CERN...
Unlike FOSS zealots, they understand the importance of using right tool for the job
sorry to wake you up from your nice dreams, Linux is the only tool used in serious science, unless propietary hardware suffers from the windows lock-down. That's why you'll see more windows boxes in labs than in theory departments (in fact it is rather hard to see a theorist using anything but linux)