The Windows operating system (Windows OS) for desktop PCs are more formally called Microsoft Windows and is actually a family of operating systems for personal computers. Windows dominates the personal computer world, running, by some estimates, more than 90 percent of all personal computers – the remainder running Linux and Mac operating systems. Windows 10 Professional Also included in our EES as a downgrade is Windows 10 Pro for Workstations, if you require this image, please email software@umn.edu to request it. The below Windows OS software will activate against our Key Management Server (KMS), therefore a product key is NOT required.