I don't know if this was addressed already... but you don't want to try XP unless you have at least 64 MB of RAM. Even then, it is very slow - also MS recommends 300MHz processor or better. W2K might be a better option for older systems.
(hide) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (show all tips)