Installation of XCode can't be closed

Hi everyone!

I have a Macbook from 2010, the white model and can't get the newest version of XCode. So I signed up as an developer and got an older version. Now I am sitting here and I got and Installation Alert because supposedly my iTunes isn't closed... Witch isn't the case. Now I am waiting that long, that I decided to not get XCode etc. but I can't stop the download unless the problem with iTunes is solved.

Please help!

Its getting on my nervese! And plz try to write easy words, because I am from Germany.

Noah