Windows XP typically requires a product key upon installation, forcing you to prove that you own a legitimate copy of the software before using it. You can bypass this restrictive requirement with Windows XP with Service Pack 3, allowing you to use the operating system for 30 days before having to register it with Microsoft. This is done during the installation phase of the software.
Insert the XP SP3 CD into the computer.
Restart the computer. Press any key to boot from CD.
Press "Enter" at the first screen and "F8" at the license screen.
Follow the onscreen instructions to choose the drive to which you wish to install Windows.
Press "Next" at the product key entry screen to bypass activation.