I downloaded the .iso file, burned it to a cd with toast, then boot up from it. I got a sort of full-screen command line. i pushed enter and it started to boot. when it finally finished, a desktop with nothing but a little window, similar to terminal. if i clicked the desktop, not right clicked, a contextual menu came up with some useless stuff. the entire sreen had black lines going down like i had an old brocken crt. what did i do wrong? please help!