Windows Update provides automatic downloads of security updates, bug fixes and patches that need to be installed on your computer. These updates are provided by Windows for a variety of reasons and are recommended to be installed automatically after they are downloaded. If a user is unsure whether she received a particular update and wants to verify whether it has been installed, she can easily do so using her Windows XP operating system.
Click the "Start" button and select "Control Panel" from the resulting menu.
Double-click "Add or Remove Programs" to open the list of program presently installed on your computer.
Click the check box next to the "Show Update" option located at the top of the window.
Locate the "Windows XP - Software Updates" header. Beneath it, you will find a list of all the installed Window's updates and the date when they were installed.
Windows Vista and 7 list software updates conveniently in the Windows Updates program, providing a one-stop shop for managing and installing new updates. Although this functionality is not available in Windows XP, users can download a third party utility called WinUpdatesList to conveniently list all the updates installed on their computer.