private void btn_loguserin_Click(object sender, EventArgs e)
    {
        string userName;
        string userPassword;

        userName = txtbx_username.Text;
        userPassword = txtbx_password.Text;

        if (userName == "" || userPassword == "")
        {
            txtbx_username.Text = "MISSING INPUT";
        }
        else
        {
            LogIn loginStatus = LogIn.getInstance();
            byte runLevel = loginStatus.LogMeIn(userName, userPassword);
            if (runLevel > 0)
            {
                Form1 form1 = Application.OpenForms["Form1"] as Form1;
                if (form1 == null)
                {
                    Console.WriteLine("Form is null!");
                    // !!! Throw an exception here !!!
                }
                else
                {
                    form1.runLevelChecker();
                }
            }
            else
            {
                txtbx_username.Text = "INVALID LOGIN";
            }

Form1 form1 = Application.OpenForms["Form1"] as Form1;