Invalid product ID on XP setup after repair reinstall

[Colt__]

Hi folks i'm totally at a loss with this one, any help would be much appreciated.
I did a repair install on a windows xp machine as I was worried some system files may have been corrupted. Now when I enter the setup after bios I reach the stage where I need to enter a product key, the first key I assumed it would be, the one written on the label on my PC didn't work.
I then tried to pull the key from the setup files I was using from the usb key, which I got from the unattend text document in the setup files, this one also comes up invalid. My last port of call was to painstakingly put the hard drive into another pc so that I could use a product key finder software on the existing copy of xp that had been used and this key also failed to my utter dismay.
Could anyone tell me what key the setup is expecting in this scenario?

 

[hang-the-9]

Few things can cause this, is the OS version the same as from the license key on the computer? If you installed XP Pro but you have a Home key for the system, it will be invalid. Also the unattended text file key is usually put in only during setups done at a company which use a volume license key.

Try just skipping the key entry at this point and after the setup go into the properties of the system and you will see an option to change product key there, enter the one on the computer and see if it works then, as long as the XP version that is installed and on the sticker match.