Microsoft has announced that it will stop supporting computers using those older operating systems as of July 13th.
The service packs contain major security and reliability upgrades. Microsoft issues security updates on the second Tuesday of each month, known as Patch Tuesday.
Microsoft recommends that its customers buy new Windows 7 PCs. Alternatively, XP SP2 users can install Service Pack 3. The procedure is described in below link.
http://update.microsoft.com/microsoftupdate