Programming is a completely different language

I got my movements and area defined out for my game. The only thing i have left to do now is keep trying to find the proper coding for internal walls. The walls i have made on the outside and they can work on the inside, but in one direction, the character wont go through it and from the other side, he can go right through it. so im trying to figure out a way to make a line completely impenetrable from any angle. IF there are any suggestions, please feel free to leave me a comment or two or give me some examples of some wall coding that works because i am stumped and cannot find any codes that work with my codes.

onClipEvent (load) {
yspeed = 2 ;
xspeed = 0;
power = 2;
friction = .8;
//gravity = 0.009; }

onClipEvent (enterFrame) {
if (Key.isDown(Key.RIGHT))
{ xspeed += power;
this.gotoAndStop("right");
} if (Key.isDown(Key.LEFT))
{ xspeed -= power;
this.gotoAndStop("left");
} if (Key.isDown(Key.UP))
{ yspeed -= power;
this.gotoAndStop("up");
} if (Key.isDown(Key.DOWN))
{ yspeed += power;
this.gotoAndStop("down");}
_rotation += xspeed;
_y += yspeed;
_x += xspeed;
xspeed *= friction;
yspeed *= friction;
//yspeed += gravity;
if (_root.ball, hitTest(_root.wall4))
{ this._x += 10;
this.gotoAndStop("right");}
if (_root.ball, hitTest(_root.wall3)) {
this._y -= 10;
this.gotoAndStop("up");}
if (_root.ball, hitTest(_root.wall1)) {
this._x -= 10;
this.gotoAndStop("left");}
if (_root.ball, hitTest(_root.wall2)) {
this._y +=10;
this.gotoAndStop("down");}}

getting in the final stretch

Still learning on my game. How to make inner walls and inner boundries that dont allow the player to go through one side and not the other. My outer walls work but only one way. im looking for some coding that will not allow the player to slip through the back.

Current programming issues HELP!

So far ive got the programming for up and down, but i cannot get the left and right to work. ive tried making my own code and copying other codes and left and right still dont work. they work in the original code i copied them from, but cease to work on mine. if anyone can take a look at my coding and tell me why the left and right codes arent working, please help!!! up and down work fine.

ball._x = 400;
ball._x = 1;
onEnterFrame = function() {
ball._x = ball._x + 4;

if (Key.isDown(Key.UP)) {
ball._y -=10;
}
if (Key.isDown(Key.DOWN)) {
ball._y +=10;
}
if (Key.isDown(Key.RIGHT)) {
ball._x +=10;
}
if (Key.isDown(Key.LEFT)) {
ball._x -=10;
}
ball._x = 5;
}

Speed Scripting

Starting today im starting tha actual programming of my game. I think its going to be intersting and the learning of the codes will be the hardest part. I have to find the code for walls and make sure nothing goes through them. Cant wait to see how its going to end! im getting anxious!