The Gateway should have the Windows XP product key on the side of the computer. The key is for an OEM version of the CD. If your Windows XP Home CD is OEM then yes it will work and to activate Windows, you will have to call Microsoft since its an OEM computer and they now requior a phone call for all OEM computers. To find out if your Windows XP Home CD is OEM, pop it in the drive and open the setupp.ini file under the i386 folder. You will find 55277OEM listed in the file if its Windows XP Home OEM and it will work great to reinstall Windows and activate it on the Gateway.