You will get disturbed when you are getting notified after updates are downloaded for windows xp that you should reboot your computer for updations to take effect. You will get warning messages every interval of time like, “Automatic  updates for your computer is almost complete and you should reboot your computer for the updates to take effect”. Automatic update will secure your pc but the warning messages will cause you disturbed.Now, you can get rid of these messages with some few steps.Follow these steps:

Disable the Automatic Reboot after Windows Update, for Windows XP Pro users

By following these steps your operating system will wait for user restart instead of restarting automatically.

• Launch RUN command in START menu (short cut as +R), Type gpedit.msc and hit enter.
• This will launch Group Policy Editor
• On left hand side you will find LOCAL COMPUTER POLICY, In this go to COMPUTER CONFIGURATION
• click ADMINISTRATIVE TEMPLATES, then go to WINDOWS COMPONENTS and click on WINDOWS UPDATE.
• You will see No auto-restart for scheduled Automatic Updates installations, Double click on it a new window will open, Click on SETTINGS tab, check ENABLE then press OK.
• Close the Group policy editor

If you are a window Home user the procedure will be different since there would be no Group policy.

Disable Automatic Reboot after Windows Update for Windows XP Home users

• Go to Run (Windows+R), type regedit (registry editor), Hit enter.
• Navigate to
  HKEY_LOCAL_MACHINE \Software\Policies \Microsoft\Windows \WindowsUpdate\AU.
• Change “NoAutoRebootWithLoggedOnUsers” DWord value to 1. This will disable the Reboot
• hit enter