Firstly, u should have atleast a pentium 3 700 MHZ, 128 mb RAM, 4 GB hardisk space 2 run it.If u dont have it, b happy with win 98.
Secondly, U can have a pirated version of win xp pro and win xp home..but u need to activate win xp home in 30 days otherwise it will stop working..not so in case of win xp. u can chose 2 not activate it and run itz pirated version smoothly.However, for installing service packs, U need 2 activate both versions of windows xp..pro as well as home.