Hi i am creating a shooting game in AS3,my problem is that i cant do what i used to in AS2.
In AS2 i used to have many SWF files for one game(main.swf, level1.swf, level2.swf ...),main.swf would open first and i was jumping from one SWF file to other using

loadMovieNum("level2.swf", 1);

and that is all you needed in AS2 game when you finish level and you want to go to next level, but in AS3 things are little bit complicated.
I only know how to LOAD level1.swf into main.swf but when i want to UNLOAD
level1.swf and jump to level2.swf nothing works for me.

Here is the code what i used

main.swf: you click a button named "my_mc" and level1.swf loads
Actionscript Code:
function newvid(event:MouseEvent) {
trace("you clicked me");
var loadit = new Loader();
loadit.load(new URLRequest("level1.swf"));
my_mc.addEventListener(MouseEvent.MOUSE_DOWN, newvid);

level1.swf:what i would want is when i click a button named load_btn it unloads level1.swf and loads level2.swf
Actionscript Code:
load_btn.addEventListener(MouseEvent.MOUSE_DOWN, loadlevel2);

This is probably easy for AS3 users but i am pretty new in all this so any help or idea would be appreciated,