Restart SetInterval

1

I’ve used a function to activate a movieclip inside another one. The function is being called by setInterval.

  
function openwindow (){
 if (_root.room:track == 2){
  clearInterval (intId);
 _root.room.windowleft.gotoAndPlay("open");
 _root.room.windowright.gotoAndPlay("open");
 }
}
intId = setInterval (_root.openwindow, 100);

After the condition met that

 
 if (_root.room:track == 2){
  clearInterval (intId);

I’ve clear the interval. But the movie contains a reply button. How can i restart the intervalID i’ve cleared to make the movie looping.