Xp Home Install - No activation needed?

[canister]

I was installing XP home on a new system I put together. Well the only XP cd I could find was an old Gateway disc someone gave me. After installing XP the activation message popped up I clicked it to activate. To my suprise it said windows is already activated. So to make sure I looked in SandraLite and it also said it was activated. I restarted my comp and once again it said to activate and the same thing happened, I went to activate and it said it was already activated and everytime I turned on my comp the same thing would happen. Well, I loaded SP2 and then it finally made me actually activate it. I mean if I never loaded SP2 I wouldn't really ever have had to activate XP at all I guess. So, has this happened to anyone else?

 

[xpoptical]

You would have had , if you made a major hardware change. Extra HD, New Motherboard etc... But if you were careful , you could avoid activation, Im surprised that it didnt scan your hardware and say.
*YOURE NOT RUNNING A GATEWAY MODEL THAT YOU GOT THIS CD WITH*
Thats what my dell win me cd sez. but i dont need it i have XP