How do I get the I tunes downloaded onto my computer ?

Nothing I get the them out I can play the songs but can;t get them in a file in my docs. I got them out the apple store once but now I am trying to get them out of the i tunes store know I have to put them into a version fomate compatitble with windows power point. I about give up someday I may figure out how to access the music I paid for. I think I connected a M-P3 player to the computer to get the songs out and I put them on my other computer and then from the M-p3 into the computer with the I tunes store. But there not compatable with poer point. one of them was becuse I made a power point presentaion out of it of the blizzard we had a few years ago lake shore drive was shutdown the art instute lions were buried in snow Stste street was empty its a cool presentation. Not my greatest choice in songs it was Wet Wille Keep on Smileing I want to do one of moonlight Sonata with pictures I have taken of the Moon rising out of the lake and pictures of wolves and stuff but the song is stuck in my i tunes stores bought paid for and not accesable to a simple person like me

HELP HELP HELP!!!!!

This issue is getting into my files seperating it from the i tunes store I can't even get into a file in music or documrnts on my computer it would be nice if I could convert it at the same time to formate I need but just getting into a file that is mobile on my computer is the first pronlem

This seems to have worked I think not sure if format is right for windows yet will try and put it in the presentation