Windows Updates are quite frequent (in spite of what some people think ;-) and it is recommended to install at least the critical updates when they are made available.
Once these have been installed, a reboot is necessary for the changes to take effect. So that you don’t forget, a small pop up window will continue to appear reminding you that you should do this as soon as possible. If you don’t want to reboot straight away then you will need to click on the [Restart Later] button, except that….

… Windows will continue to remind you every 10 minutes that you haven’t yet rebooted your computer. Microsoft insisting that I reboot my computer is a little frustrating, especially since I like to have the choice of rebooting my computer when I want to and not because I am forced to…
Another joke, if I can say so is that after you have installed the updates and pressed the [Restart later] button, if you leave your computer unattended for a long period of time then Windows will take the initiative of rebooting your computer for you without asking!!! Just so that it is a little better, there is a 5 minute period where you can stop this automatic reboot from happening (for the next 10 minutes or so anyway).

If you are like me and have had enough of these reminders then there are 3 possibilities available to you:
1.For Windows XP Home and Professional users
After having downloaded, installed the updates and clicked on the [Restart Later] button, do the following:
Click “Start”, “Run” and type “net stop wuauserv”. Click “OK” so that the “Automatic Updates” services are stopped.
This service is the one that allows you to run the Windows Updates. If you decide to stop this service then you have probably already downloaded the updates already and you don’t want the automatic reminder message to appear every 1à minutes ;-). This window will no longer appear during your session.
This will also leave the service to automatically start itself the next time you reboot the computer so it will be as if nothing happened.
This means that this solution is not a one off fix and you will need to apply this trick each time that you receive a new update that asks for a reboot. To make your life simpler, you should create a shortcut on your desktop with the command line instructions. This way you will be able to stop the service each time it is necessary by simply clicking on the link. It is simple and practical.