And you didn't think that information to be relevant enough to be
included in your original post? Your post was not correct, the correct
question would be something like "How can I replace a pirated Windows XP
product key with a valid one? Or, "How can I upgrade a pirated Windows
XP Pro installation with a legitimate copy, can I simply do an in-place
upgrade to register a legitimate product key?"
How to change the Volume Licensing product key on a computer that is
running Windows XP SP1 and later versions of Windows XP
http://support.microsoft.com/kb/328874
John