itunes wont quit.

i decided to change my itunes toolbar icon, and in doing so i some how created two versions of it or something. any way, i didn't really care, as it worked fine for a few months until i opened itunes to play some music, and the icon had that dot under it to say it was open, and activity moniter and force quit apps said it was, but i couldn't open or force quit it. i had to use the other itunes- the one without the changed icon, but the other one is still open. i have quit itunes in terminal, but it just quit one of them. any help?