Microsoft frequently releases updates to their operating system every week or couple of weeks, though many desist the frequent updates, we recommend users to keep their system up-to-date by applying the updates released by Microsoft.
That said, tracking all the installed updates is not pretty straightforward and you need to visit the control panel and select the option to see all the installed updates. This however is a bit easier in Windows Vista through the Programs > View Installed updates option.
Though both Windows XP and Windows Vista just show you the updates that were installed and not the actual files that were installed during the update process. WinUpdatesList on the other hand is a handy freeware utility that displays the list of all Windows updates (Service Packs and Hotfixes) installed on your local computer. For hotfix updates, this utility also displays the list of files updated with these hotfixes. In addition, it allows you to instantly open the Web link in Microsoft Web site that provides more information about the selected update, uninstall an update, copy the update information to the clipboard, or save it to text/HTML/XML file.
So if you are looking to view the list of installed hotfixes and service packs on your Windows PC, download WinUpdatesList and view it easily.