That's like saying, *Just try different things until something works.* Gee,
thanks!
I can't recall anything in XP setup that requires your name. All
Microsoft knows is a big pseudorandom number based on things in your
compter like the ethernet MAC address, memory and disk size, video
card and mobo model, etc. Microsoft keeps this number, and the
software keys. Nothing else. If that key is used on a machine that
has a different number won't register except under specific cases.
Your friend has nothing to activate unless he reinstalls (which I
would). As long as he's made zero or a small # of hardware changes it
will reactivate. If he's made a bunch of changes (video card, ethernet
card, added memory and disk before installing) he may have to call
Microsoft and from what I'm told they are pretty easy about the OK.
Filling out those bingo cards that come in the box have nothing to do
with activation and as far as I can tell, never did anything.
If it's an OEM copy of XP you can't change the motherboard.