Download and install Windows XP Service Pack 3 from: Microsoft Download Center
1. Click on the download button on the website. Once the Security Warning dialouge box appears, click on Save.
2. Save the file to your desktop by selecting "Desktop" from the left side pane or from the drop down menu in the "Save in:" section.
3. Double click on the file “WindowsXP-KB936929-SP3-x86-ENU.exe” on the desktop, the installer then extracts files to a temporary location. At the following screen click Next.
4. Click "I agree" and then click Next.
5. The installer will give you the option to create a location for creating a backup of your current systems files. Choose the default location and click Next.
6. The installer then inspects your configuration.
8. After the installer is done it will ask if you want to reboot the computer now. PLEASE reboot the computer now.
9. After the computer has rebooted you delete the file “WindowsXP-KB936929-SP3-x86-ENU.exe” from your desktop.