Microsoft has annouced on their TechNet blog that come April Windows XP SP2 and a string of other versions of Windows will no longer received support.
On 13th April 2010, Windows XP SP2, Windows 2000 (Professional & Server editions) and Windows Vista RTM will come to the end of life according to Microsoft and will no longer be supported by Microsoft nor receive updates from Microsoft/Windows Update.
For Windows XP SP2 users the solution is easy. Install Service Pack 3 (32-bit only). Same for Vista folks. Installing the latest service pack will help you to continue receiving support from Microsoft.
For Windows 2000 users, for both desktops and servers it has now come to the point where you need to start seriously thinking about upgrade or buying new equipment. Windows server is now up to Windows Server 2008 R2 and is released on alot of major hardware vendors servers. For Windows 2000 Professional users, you unfortunately do not meet the upgrade requirements of Windows 7. If you prefer to upgrade, you will need to upgrade first to Windows XP before proceeding to Windows 7, according to Microsoft.
For more information, read the post here.