Something's wrong with my computer's audio?

i installed this game from BigFish called "FAIRIES" and then after I played and removed it from my pc, the audio has this echo that i guess my pc caught from the game (bec the game has echoing sound effects) how do i get rid of the echo on my pc? I already checked the advanced volume controls. everytime i watch a video or play something on itunes, there is this echo going on.how do i put the audio back to normal? please help!