A family of PC (Personal Computer) operating systems developed by Microsoft. Before Windows, most PC’s were limited to DOS, or a very DOS-like user interface. These old systems did not really have many (if any) graphics and usually required special commands and codes to be typed in order to carry out even simple functions. Not long after the Macintosh arrived on the scene with it’s GUI (Graphic User Interface) Microsoft came out with Windows, aptly named because pertinent information is contained in layers of windows that can be opened on the screen (much like the Mac). Windows is by far the most dominant OS used on PC’s today, and there are many different versions, including Windows 95, Windows 98, Windows 2000, Windows CE, Windows NT, etc.