Usually the official license key for the PC is on the case somewhere. You can try to change the serial number via this procedure to the correct license key to see if it takes:
wonder if anyone could help me out.
i have had a pc for some time now (probably about 6 years) it is on XP, when i upgraded to a laptop i gave my mum my PC along with everything that came with it discs the lot.
my step father decided to try and be clever and sort out the pc as it was going slow and input an XP disc which was a copy of one of his friends who told him if he installed that it would fix the pc.
the pc is now not registered as a genuine system which means the pc can not receive updates etc.
i have searched all of the stuff i gave my mum and am unable to find the system restore disc to get it back to factory settings and start it a fresh for my mum.
does anyone know how i can do this without the restore disk?
i am not bothered about losing everything on the pc and start a fresh so if anyone can give me any ideas etc please give me a shout
thanks in advance