WindowsXp
Operating system of the Windows NT family of Microsoft Corporation. It was released on October 25, 2001 and is an evolution of Windows 2000 Professional. The name XP comes from eXPerience. Unlike previous Windows 2000, which came in both server and client versions, Windows XP is a client-only system.
Windows Server 2003
The operating system of the Windows NT family from Microsoft, designed to work on servers. It was released on April 24, 2003. Windows Server 2003 is a new version of Windows 2000 Server and a server variant of the Windows XP operating system.