My computer recently completely messed up majorly, I took it to get repaired and the guys there said they can't and have never seen anything like it. Some guy my mum knows had a look at it and he managed it to fix it. But in doing so he used his Windows XP. So now when it asks for the activation key, I try my computers original one and it doesn't work and for some unknown reason the guy who fixed it won't give me his, and he has moved elsewhere and is completely untraceable. So, what can I do to get a new activation key for Windows XP? Will it involve calling Microsoft and as far as hardware changes go, the computer has had none at all done to it.