Edit the actions of a .swf without the .fla file

i was sent a very funny .swf file and i want to make it a screensaver with my screentime software but at the end it has a play again button and that is no good for a screensaver so is there a way to edit the actions of the .swf without using the .fla file. and i have tried to import into flash MX04 and MX but it just makes 700 keyframes and no sound or animations.

can anyone help.