Windows Installer (Windows XP/2003) is a configuration and installation service enabling software users to install and configure their applications and products efficiently. Without installing the software products their features can be advertised and user customizations can be added depending on the operating system. It has various features which include Custom Action Execution On Update and Shared Component Patching Resiliency During Uninstall. The recent version of any component is made available for all the products. Whenever any update has been uninstalled, custom action is called so that there can be some addition or change in it. Advertisement of applications is also supported.