Windows 2000 (also referred to as Win2K, W2K or Windows NT 5.0) is a 32-bit preemptible, interruptible graphical business-oriented operating system, which has been designed to work with either uniprocessor or symmetrical multi processor (SMP) based Intel x86 computers. It is part of the Microsoft Windows NT line of operating systems and was released on February 17, 2000. Windows 2000 comes in four versions: Professional, Server, Advanced Server, and Datacenter Server.