IIRC XP was not out when EU2 was released. 
Anyway no problems with EU2 and XP.
As for where to buy it, that depends somewhat on where you live.
On line e-bay, or amazon ...
In North America and else where you can get bundled with other games, Crown of the north NA version has a copy included as does the conquerer pack and others.
Anyway no problems with EU2 and XP.
As for where to buy it, that depends somewhat on where you live.
On line e-bay, or amazon ...
In North America and else where you can get bundled with other games, Crown of the north NA version has a copy included as does the conquerer pack and others.