problem with animation

at the end of the game window appears GameOver. I press F1 and do a restart, now GameOver window appears instantly. Here is a script that is on it.

public class gameOver : MonoBehaviour {

public static bool isGO = false;
public Animator anim;
public static bool restart = false;
void Start () 
{
    anim = GetComponent<Animator>();
}


void Update () 
{
    

    if(isGO)
    {
        anim.SetBool("isGameOver", true);
    }

    if (Input.GetKey(KeyCode.F1))
    {
        Application.LoadLevel(1);

    }
  
}

}

Why GameOver window appears immediately?

I am quite sure that this problem is being caused by your boolean isGo. Are you sure this boolean is on false after you restarted your game with f1?
Since this bool is static you most likely access it in other scripts, you should take a look at this.

if(isGO)
{
anim.SetBool(“isGameOver”, true);
}
else
{
anim.SetBool(“isGameOver”, false);
}

or

anim.SetBool("isGameOver", isGO);