its usually in Program files(or programs if you have vista). But if you are using the dekaron client instead of 2moons client, it maybe under gamehiUSA folder
EDIT to statement below: Syberboy, GameHi_USA is the default folder you get when you install dekaron from gamehi's website. It would be equivalent to the acclaim folder in program files. If you double click it (GameHi_USA) then it opens to another folder, GlobalDK, then bin.