Operating System:
An operating system (OS) is a set of programs containing instructions that work together to coordinate all the activities among computer hardware resources. Most operating systems perform similar functions that include starting and shutting down a computer, providing a user interface, managing programs, managing memory, coordinating tasks, configuring devices, establishing an Internet connection, monitoring performance, providing file management and other utilities, and automatically updating itself and certain utility programs. Some operating systems also allow users to control a network and administer security.
Windows:
A stand-alone operating system is a complete operating system that works on a desktop computer, notebook computer, or mobile computing device. Some stand-alone operating systems are called client operating systems because they also work in conjunction with a server operating system. Client operating systems can operate with or without a network. Other standalone operating systems include networking capabilities, allowing the home and small business user to set up a small network. Examples of currently used stand-alone operating systems are Windows 7, Mac OS X, UNIX, and Linux.