e come faccio a bloccarlo?

per muoverlo ho usato questo :

onClipEvent (enterFrame) {
Ysquare = _root.search._Y;
Ydiff = Ypos-Ysquare;
Ymove = Ydiff/2;
_root.search._Y = Ysquare+Ymove;
updateAfterEvent(enterFrame);
}
onClipEvent (enterFrame) {
Xsquare = _root.search._X;
Xdiff = Xpos-Xsquare;
Xmove = Xdiff/2;
_root.search._X = Xsquare+Xmove;
updateAfterEvent(enterFrame);
}