Microsoft first began development of the Interface Manager (subsequently renamed Microsoft Windows) in September 1981. Although the first prototypes used Multiplan and Word-like menus at the bottom of the screen, the interface was changed in 1982 to use pull-down menus and dialogs, as used on the Xerox Star. Microsoft finally announced Windows in November 1983, with pressure from just-released VisiOn and impending TopView.

Windows promised an easy-to-use graphical interface, device-independent graphics and multitasking support. The development was delayed several times, however, and the Windows 1.0 hit the store shelves in November 1985. The selection of applications was sparse, however, and Windows sales were modest.

XP is a whole new kind of Windows for consumers. Under the hood, it contains the 32-bit kernel and driver set from Windows NT and Windows 2000. Naturally it has tons of new features that no previous version of Windows has, but it also doesn't ignore the past--old DOS and Windows programs will still run, and may even run better.