Making sure that your Windows operating system is always up-to-date is essential for keeping your machine free of bugs, viruses, and hackers. The method for doing this is using Windows Update.
To access Windows Update from your Start Menu, press Start > Windows Update or Start > Programs > Windows Update.
To access Windows Update directly from your web browser, go to http://windowsupdate.microsoft.com.
I want to download and install any critical Windows updates that are needed.
How to do it:



Keeping your system up-to-date is an important process that is often forgotten. Windows XP allows you to never have to bear the responsibility of remembering to manually update your system again with the automatic update feature. Windows XP downloads, updates and notifies you when they are ready to be installed, or you can choose to be notified before the updates are downloaded.
Follow these steps:

Troubleshooting:
Some of these options are "greyed-out" and are unselectable.
If your computer is being managed in an AD (Active Directory) environment, some of the options may be unavailable to you. In this case, it is likely that these updates are reaching your computer automatically and you may not even need to follow the instructions in this tutorial.
Click Start > All Programs > Windows Update> Review Your Update History (under Options)
This update is KB931836. To confirm that it as been applied to your machine, locate this update on the History list.

If you do not see this update listed, you can manually apply it by clicking on this link DST Windows Update 02/2007
Last Updated: Jan.13, 2012