Microsoft is going to end support for Windows XP Service Pack 1 and 1a next Tuesday. Critical updates and security fixes will only be available for users who have or upgrade to Service Pack 2.
Microsoft generally only guarantees support for a service pack for one year after the release of the next pack. Windows XP SP1 has been around for almost four years, while Service Pack 2 was released in September 2004. Microsoft routinely ends support and updates for its older operating systems after several years.
The company continued supporting Windows 98 and Millennium up until July 2006.