To reinstall Windows XP by starting your computer from the Windows XP CD, follow these steps: Insert the Windows XP CD into your computer's CD drive or DVD drive, and then restart your computer.
When you receive the "Press any key to boot from CD" message on the screen, press a key to start your computer from the Windows XP CD.
The following message on the Welcome to Setup screen will appear:
This portion of the Setup program prepares Microsoft Windows XP to run on your computer: To setup Windows XP now, press ENTER. To repair a Windows XP installation by using Recovery Console, press R. To quit Setup without installing Windows XP, press F3.
Press ENTER to set up Windows XP.
On the Windows XP Licensing Agreement screen, press F8 to agree to the license agreement.
Make sure that your current installation of Windows XP is selected in the box, and then press R to repair Windows XP.