IIRC, IO, WGA will not run under Xp without SP2 so you hae to download/install all updates up to that pooint before the WGA will appear.
Never been keen on cracks, you have no idea "what else" you can get as there are so many holes in XP someone could take advantage of that.
There is a "safer" way to get around the WGA checks, but since that can be used to make MS think that an illegal copy of XP is "legit" I ain't sure if we allowed to talk about it.