i find the brain will only repeat things because you want to learn the song because you like the song enough to listen to it a few times. the brain only wants you to be happy, but doesn't realized how annoying it is to have the same song run over and over... i've had 3 songs overlap in my head at times. and i'll always have at least one song running just to keep focused. when i get one in my head, i have to simply stop listening to it.
i have found that certain types of music are more likely to stay. anything that has two tracks for the left and the right, like trance. or high voices. the low ones don't seem to stick.
and sometimes the only way to remove the song is to place another song over and and the one i use, and it works almost every time, is the theme to the muppet show. try it, you'll be surprised how well it works.
---Mike Savad
MikeSavad.com