help please - needs more sources

[amguevar]

Hello everyone..
perhaps my question is too easy to solve but i have no idea how to do it... I have searched and double clicked the songs i want to download. Some of them still sice long time ago in the list waiting to be downloaded but it´s says that needs more sources... i´m tired of waiting and now i know that those songs will never download, i keep choosing "find more sources for download" but it doesn´t work so.. now i just want to DELETE that list so the new downloads will be quicker,..,.. how do i do that? there´s a button that says 2trash" but doesnt work, and also doesnt work the button that says delete inactive downloads, (or something similar..) how do i delete my files that didn´t download?
please help..