A family member has a failing computer running XP Pro whereas I have a spare drive on my own computer with an unused XP Pro installation already set up. My idea is to back up all his files/folders etc using the Back Up facility within Windows Live OneCare and then set him up on my spare drive. All XP installations in this house have passed Microsoft validation however, he does not have an installation CD but I can get his Product Key. I have two questions. What is the best method of preparing a computer for a fresh installation of XP Pro (is formatting the HDD too extreme)? Secondly, if I use my installation CD to re-install XP Pro on his computer but when the time comes to enter a Product Key, I enter HIS Product Key rather than my own, can that work? Are Product Keys only specific to the program/application being installed or are they specific to the individual installation CD being used?