Insert your Windows XP CD inside your computer's CD or DVD drive. Select Install Windows. The Windows XP installation wizard begins. Select Upgrade to upgrade your installation from Window 2000 to Windows XP. Do not perform a clean installation if you want to keep your existing programs, files and personal data. A clean install wipes your computer clean. Accept the Windows XP license agreement, then click Next. Enter the product key and click Next. A report displays informing you of potential issues with the upgrade. For example, a specific program may not work. Select Yes to get updated files from Microsoft's website. This allows you to get the latest fixes prior to your upgrade. If you are not connected to the Internet select No. The computer will reboot several times during the upgrade process until the upgrade is complete.