|The Product Key your friend (or you) used was accepted by Window's Setup, but you're getting that message because the Product Key was found to have been fraudulently used by someone when the Windows Genuine Advantage program checked your Windows installation. |
That program checks for Product Keys found to have been fraudulently used e.g. in the background, probably by referring to data on the Microsoft web site, when your computer is connected to the internet.
If your computer has the official Microsoft label stuck to the outside of the case like it's supposed to, you can change the Windows Product Key to the key on that, if the version of Windows you installed is the same as on that sticker - Home, Pro, MCE 200x, or Pro 64 bit.
If you have a brand name system computer, the version of XP that was originally installed is almost always an OEM licensed version.
MCE 200x versions are always OEM licensed versions.
(MCE 200x versions have more data than can fit on one CD.)
If you have a generic desktop system, the sticker may be for an OEM licensed version, or a Retail licensed version.
If the original CD has Genuine Windows Advantage printed on, it's probably a Retail licensed version, it's got Not For Resale in the outer holograms on the CD, and it's NEVER supposed to be used with any computer or Product Key except for the one it was bought from Microsoft for - the Product Key used was probably fraudulently used.
That's the CD that is sent to you by Microsoft when it's found you have a fraudulent Product Key, then you pay Microsoft to have a legitimate CD and Product Key sent to you.
If you're not sure which licensed version was installed, the volume label of the original CD you used - e.g. the label you see for the optical drive letter when you insert that CD in a drive in Windows - is unique to the type of Windows installation it is. You can search the web using that volume label to determine whether it's version is OEM, Retail, or Volume licensed.
In most cases if it's Volume licensed, the Product Key used was being used illegally, according to Microsoft's standards, unless the computer is used for a company or institution that a Volume licensed version can be appropriate for.
If the CD or DVD used to install Windows was a copy of a Windows CD, or a "slipstreamed" CD or DVD, if it has no volume label, open up SETUPP.INI in the \i386 folder on the CD or DVD.
The Product ID - the number after Pid= can be searched with on the internet to find out which licensed version it's for.
See this -
Get IT Done: Change the product key on Windows XP
The WMI script file method only works for Volume licensed versions of XP.