How reset movie of graph?

1

hello…

I have problem about reset movie of graph.
I have one combobox and in labels is “—select—,Underdamped”
then seclet “underdamped” in lables of combobox it plot graph one line.
then click button “reset” and it reset line of graph.I want reload then select “underdamped” in lables of combobox .but it will dont work.
why?. I dont understand.
how i write actionscript ?
can someone help me?
thanks yous
this is code

this.createEmptyMovieClip(“graph_mc”,this.getNextHighestDepth());
graph_mc.moveTo(100,300);
graph_mc.lineStyle(2,0xff0000);
var t:Number = 0;
var i:Number =-98;
var start_bn:Boolean=true;
LO = new Object();
LO.change = function(EO)
{
c1Value= c1.getSelectedItem().label;
checkValue();
};
this.onEnterFrame=function()
{
Go=1.5*(1.06*Math.exp(-t)*Math.cos(Math.sqrt(8)*t-19.47));
if(c1Value==“Underdamped”)
if(i<148)
{

graph_mc.lineTo(198+i,140-190Go/150i);
t+=1/7;
i=i+3;

}
}
reset_btn.onPress=function(){
unloadMovie(graph_mc);
t= 0;
i=-98;
start_bn=false;

}
_root.c1.addEventListener(“change”, LO);