how to retrieve an old itunes library

I would like to retrieve my old itunes library on a new computer. My old computer died and no longer turns on or works. I was not able to transfer the library and my music files to an external drive. I don't know if there is another way to retrieve my music or not? I am able to log in using my apple id and password but when I click on available downloads there is nothing and not sure if there is something else I need to do or if all is lost?