When we mention Windows VPS we mean a Virtual Private Server that runs the operating system from Microsoft known as Windows Server. There are a number of different versions of Windows server in use today, some using less system resources than others. When we mention Linux VPS we mean any Linux based operating system running on a Virtual Private Server. Since there are far more flavors of Linux than Windows we won't go into too much detail on the different operating systems suffice it to say that the majority of them are free, with the exception of a few enterprise Linux distributions that come bundled with tech support (such as Red Hat Enterprise Linux).
A Windows VPS occupies the intermediary web-hosting position between cheaper, but resource starved shared servers, and high-end dedicated hosting. Each VPS will be allocated unique hardware resources, and will operate in an entirely unique instance of the Windows operating system. This provides several powerful benefits, not the least of which is the power you gain: because your Windows installation is isolated from other customers, you are at liberty to alter it to precisely match any need or desire through unrestricted & remote administrative access.