How to disable buttons in a level

Right now I’ve got 3 different movies. The first .swf is simply the background and is level 0. It loads the second .swf into level 1 when it loads. The second .swf has buttons that when clicked will load the third .swf into level 1. My problem is that when the third .swf is loaded into level 1 the buttons are still active from the second .swf. Is there any way to disable the buttons?