- Aug 18, 2003
i bought a used computer from someone that they had assumed dead. i have repaired it, and i had to format the hard drive. there is a "certificate of authenticity" for windows xp home edition, with the product key on the back. of course, after a format, any os that was on it is gone, but i would like to know if i can still use the key to reinstall xp. finding the microsoft phone number has proved to be like chasing my tail....