Heh well if you like learn the activation process by ms.
Trial and error helps it'll give you a better understanding of what some other know it all says online. :/
XP, vista 7 and even 8 if your unsure of something ask microsoft themselves.
They have a online chat, whatever you do with those keys make sure you stay in the right and abide by ms.
Also there are some good microsoft sites then this forum who will clear up any questions or concerns you got for ms products.
If they say yes for activation, listen to what they tell you, if they so no have them explain why and abide by them.
Problem solved.