Just add an if statement.
Put this on the frames you want it to snow.
_root.snow = true;
and this on the ones you dont want it to.
_root.snow = false;
onClipEvent(load) {
this._alpha=random(70)+20;
this._width=this._height=random(4)+4;
this._y=random(640);
this._x=random(480);
fall_speed = 1+Math.random()*2;
k=-Math.PI+Math.random()*Math.PI;
rad=0;
centerX=320;
centerY=240;
}
onClipEvent(enterFrame) {
if(_root.snow == true){
rad+=(k/180)*Math.PI;
this._x+=Math.cos(rad)+ms;
this._y+=fall_speed;
ms=(centerX-_root._xmouse)/100;
if (this._y>480) {
this._y=0;
}
if (this._x>640) {
this._x=0;
}
if (this._x<0) {
this._x=640;
}
}
And you might be putting the movie clip on every frame.