Scoring without FPS Or timer

Hello Im trying to make a small Unity game in which the player explores a large free roam world in search of "Coins", Where each coin that collides with the First Person Controller will add to the score in a GUIText. I have the window set up to show my score but i do not know how to link all the components so that the score will appear in the Window. I tried using this code. . .

var windowRect : Rect = Rect (20, 20, 120, 50);
function OnGUI () {
    windowRect = GUI.Window (0, windowRect, WindowFunction, "Score");
}
currentScore.ToString();
static var currentScore : int = 0;
function WindowFunction (windowID : int) {
// convert the variable scoreNumber which is an integer to a string

// set this to the text value of your guiText to display itguiText.text = currentScore;

// A function specifically for detecting collisions with colliders 
// that have had the Is Trigger flag set in the inspector
function OnTriggerEnter(collisionInfo : Collider){
// if the current gameObject of the collider stored in the collisionInfo
// variable has a tag of "battery" (ie, we have hit a battery)
if(collisionInfo.gameObject.tag == "Coin"){            
// Increment the global score variable declared in the by 1 
// ++ is short hand for currentScore = currentScore + 1;
currentScore++;            
// Play a sound to confirm we have picked up a battery
// Remove this particular battery from the scene (the object whose collider we have hit)
Destroy(collisionInfo.gameObject); 
}    
}
}

And im guessing several of you could point out the problems in my script. I am relatively new to Unity and Java. I appreciate any help.

    var windowRect : Rect = Rect (20, 20, 120, 50);
    var currentScore : int = 0;
    var Tag = "Coin";

    function OnGUI () {
        windowRect = GUI.Window (0, windowRect, WindowFunction, "Score: " + currentScore);
    }

    function WindowFunction (windowID : int) {
        currentScore.ToString();
    }

    function OnTriggerEnter(collisionInfo : Collider){
    if(collisionInfo.gameObject.tag == Tag){
        print("collided");          
        currentScore ++;
        print(currentScore);         
        // Play a sound to confirm we have picked up a collectable
        Destroy(collisionInfo.gameObject); 
        }    
    }

hope this helps, I've just tidied up your code and reorganized it to make a bit more sense. with these changes I got it to work for myself so hopefully you can get it to work

Scribe