Windows Server 2003 was released as an upgrade to Windows 2000 Server. Additional features in Windows Server 2003 include. Windows 2003 server support remote desktop feature but in 2000 remote desktop feature was not supported. Window 2003 server includes IIS server in it. That is the biggest advantage on top of better file system management. You can change the domain name at any time with help of ntdsutil command, without rebuilding the domain that is not possible in 2000. In 2000 support maximum 10 users access shared folder at a time through network but in 2003 no any limit.