If dynamic text box 'hp' = 0 or less, than play scene

if dynamic text box ‘hp’ = 0 or less, than play scene
how do i do that. when my badguys shoot they dont do even numebrs of dmg. so it might be -1 or -5 etc…

one more thing. if u know how to do this. i want to play a scene when all guys die. like i was thinking, to do something like this,
on clip load
person = 0

when he dies on the last frame, i put person = 1
and for my actions frame put something like this
if person = 1 and person2 = 1 and person3 = 1 then
gotoandplay scene “win”

can u help me out a bit?

heres my code for ammo and gun and reload.
[AS]stop();
//
shot = new Sound();
shot.attachSound(“deagle”);
reload = new Sound();
reload.attachSound(“de_clipin”);
empty = new Sound();
empty.attachSound(“empty”);
//
Mouse.hide();
//
gun.onMouseMove = function() {
this._x = _xmouse;
if (this._x<80) {
this._x = 80;
}
updateAfterEvent();
};
//
gun.onMouseDown = function() {
if (ammunition.ammo) {
c = 1;
_root.attachMovie(“hole”, “h”+c, c);
_root[“h”+c]._x = _root.sights._x;
_root[“h”+c]._y = _root.sights._y;
this.play();
shot.start();
ammunition.nextFrame();
} else {
empty.start();
}
};
//
sights.onMouseMove = function() {
this._x = _xmouse;
this._y = _ymouse;
if (this._y>310) {
this._y = 310;
}
updateAfterEvent();
};
//
reloadGun = new Object();
reloadGun.onKeyDown = function() {
if (Key.isDown(Key.SPACE) && ammunition.reloadAllowed) {
reload.start();
ammunition.gotoAndStop(1)
}
};
Key.addListener(reloadGun);
[/AS]