Product key - Microsoft Computers & Internet

Assuming you mean the product key for Windows, the product key should be on a sticker, usually on the bottom of the laptop. It is probably 25 digits mixed numbers and letters. You should have the disk it came with to install it - sometimes the product key will work with a disk from a different computer, but if the setup disk and your key are different versions it will not work. An example: If you do not have the original setup disk your computer came with, and your computer has XP home and you borrow a disk from someone but it is XP Pro, your number will not work. If your original disk was for XP home and it was with SP-2, (SP = Service Pack) a disk without SP-2 will not work. Plus, the original disk(s) usually came with the drivers you will need to reinstall Windows. You would be pretty lucky to install Windows and not need to download drivers to finish installation. Original setup disks from the manufacturer are not that expensive, and save a lot of time and frustration.