Login String to Bool Errors

I dont exactly see why im getting these errors but i would much appreciate it if i got some help on this.

Here are the errors...

 Assets/My Assets/Scripts/Network/MultiPlayer/Login.cs(27,17): error CS0029: Cannot implicitly convert type `string' to `bool'
 
 Assets/My Assets/Scripts/Network/MultiPlayer/Login.cs(33,17): error CS0029: Cannot implicitly convert type `string' to `bool'

Here is my simple login script (its only temporary but it might be a base)...

using UnityEngine; using System.Collections;

public class Login : MonoBehaviour {

 public string UserName = "UserName";
 public string passwordToEdit = "My Password";
 public bool isUserNameCorrect = false;
 public bool isPasswordCorrect = false;
 
 public bool UserNameFilled = false;
 public bool PasswordFilled = false;
 public bool PasswordCheckFilled = false;
 public bool EmailFilled = false;
 public bool EmailCheckFilled = false;
 public string CheckIfBot;
 public bool CheckIfBotCorrect = false;
 
 // Use this for initialization
 void Start () {
 
 }
 
 // Update is called once per frame
 void OnGUI () {
     
     if(GUI.TextField(new Rect(Screen.width / 2, (Screen.height / 2), 200, 20), UserName)){
         if(UserName == PlayerPrefs.GetString(UserName)){
             isUserNameCorrect = true;
         }
     }
     
     if(GUI.PasswordField(new Rect(Screen.width / 2, (Screen.height / 2) - 50, 200, 20), passwordToEdit, "*" [0], 25)){
         if(passwordToEdit == PlayerPrefs.GetString(passwordToEdit)){
             isPasswordCorrect = true;
         }
     }
     
     if(GUI.Button(new Rect((Screen.width / 2) + 50, (Screen.height / 2) - 100, 125, 25), "Login")){
         if(isUserNameCorrect == true | isPasswordCorrect == true){
             Application.LoadLevel(1);
         }
     }
 }

}

I know there are variables that are unused atm but i like to complete a section of a script completely at a time so that would be why those arent being used.