A family of operating systems from the Microsoft Corporation, standard on most PCs.
Microsoft's standard PC operating environment before the release of Windows 95. Not strictly speaking an operating system in its own right, more an add-on which provides DOS with a GUI.
Developed and released in parallel with the 9x family, were intended more for use in office and network environments, supposedly more robust but usually requiring a more powerful computer.
A version of Windows intended for business users, the successor to Windows NT.
Intended to bring together and replace the different 9x and NT versions of Windows.
Released in 2007 and intended to replace XP. Was released in six different versions, with varying capabilities and prices.