need help urgent direct 9.0c in winxp sp2

I've problmes with directx 9.0c.
i can't instal directx in win xp sp2 what i´ve to do someone helpe me!!!!!!!!!!!!!
wen i gona to instal dirctx 9 the stup din´t show th instaloation of directx 9.0.c and i cant play some games like world of warcraft,.
if u kan help me i'm extrimly helpful...