Well, here’s how to make your Window XP genuine if you’ve recently re-installed your Windows XP and can’t find your original Product ID (and installed an illegal version). Windows has no online solution but this method works good if you are having trouble validating your Windows XP. (and you’ve paid for it!!!)
Step 1: Download the license.reg file.
Step 2: Double click the file, choose yes when prompted.
Step 3: Go to Genuine Microsoft Software and click on “Validate Windows” over on the right to check whether it worked.
*Note: This is for people who have purchased a legal copy of Windows but have to resort to installing a cracked copy because either they lost their original disc or product ID. We don’t condone any illegal copying.