Windows NT 5

Windows 2000 (also referred to as Win2K) is a preemptive, interruptible, graphical and business-oriented operating system designed to work with either uniprocessor or symmetric multi-processor 32-bit Intel x86 computers. It is part of the Microsoft Windows NT line of operating systems and was released on February 17 2000. It was succeeded by Windows XP in October 2001 and Windows Server 2003 in April 2003. Windows 2000 is classified as a hybrid kernel operating system.
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Windows 2000