Shooter

hey im just wanting a lil more help on my game i have another section to it. it is a shooter. i was hoping someone can let me know how i stop a custom mouse curser going over a certain mc. i am using this code for the custom mouse curser.

onClipEvent (enterFrame) {
 setProperty(this, _x, _root._xmouse);
 setProperty(this, _y, _root._ymouse);
 Mouse.hide();
}

and im also hoping someone can direct me to a tutorial on a shooter tut so that i can have random enemy’s poping up in windows and have hittargets on them.

thanks in advance.