Microsoft Windows XP Service Pack 3 is the latest version of the Service Pack for XP.  Service Packs are culminated updates for Microsoft’s range of operating systems. To make it easier for customers to get these updates and enhancements, Microsoft periodically combines them into a single package, and makes that package available for all Windows customers.  Windows XP Service Pack 3 (SP3) includes all previously released updates for the operating system. This update also includes a small number of new functionalities, which do not significantly change customers’ experience with the operating system. Service Pack 3 features fixes for several bugs and other latest updates.  Windows XP Service Pack 3 also advised that the best way to get latest updates is to keep the Windows Update feature turned on.
Note: Customers running Microsoft Dynamics Retail Management System (RMS) are advised to install a hotfix for a Microsoft Dynamics RMS issue prior to installing Windows XP SP3.