Removing a movieClip

Hello

I have a movie that I want to use to display videos from YouTube. I put this action on a button to load the first movie:

     on (release) {
_root.createEmptyMovieClip("video_mc",10000);
_root.video_mc._x=105
_root.video_mc._y=105
_root.video_mc.loadMovie("http://www.youtube.com/v/lsyelAUH6pI");
}

I put a similar action on a second button to load another movie and it does but the first movie continues to play:

on (release) {
_root.createEmptyMovieClip("video_mc",10000);
_root.video_mc._x=105
_root.video_mc._y=105
_root.video_mc.loadMovie("http://www.youtube.com/v/fZCgAc4UMeM");
}

I searched several forums and tried this:

on (release) {
_root.video_mc.swapDepths(600);
_root.video_mc.removeMovieClip();
_root.createEmptyMovieClip("video_mc",10000);
_root.video_mc._x=105
_root.video_mc._y=105
_root.video_mc.loadMovie("http://www.youtube.com/v/fZCgAc4UMeM");
}

but it doesn't work. I would very much appreciate any help with this as I am out of my depth here. Thanks.