Table Layout Panel Problem :/

hi everyone i have a trouble this problem. i have 5x5 columns and rows i create a game to catch button. when the button create random cell location in the panel some button is re-write in to the cell and  i have to click 2 times for each cell :/.
how can i fix it? how can i delete if there is a button in the same location ??
-----------------------------------------------------------------------------------------------------my codes

int sayi = 0, mycolumn = 0, myrow = 0;
double süre = 00;
string[,] myarray = new string[6, 6];
      

 private void timer1_Tick(object sender, EventArgs e)
        { 
            Random ram = new Random();


            Button btn1 = new Button();
            btn1.Width = 65;
            btn1.Height = 45;
            btn1.Text = "X";

            btn1.Click += new EventHandler(button3_Click);

            //------------------------------------------------------
           
            mycolumn = ram.Next(0, 5);
            myrow = ram.Next(0, 5);

            Hesap(mycolumn, myrow, btn1);
             
        }
        public void Hesap(int a, int b, Button btn1)
        {
           
            if (tableLayoutPanel1.Controls.Count < 36)
            {

                if (myarray[a, b] == null)
                {

                    myarray[a, b] = "have";
              
                    tableLayoutPanel1.Controls.Add(btn1, a, B);
                }
                else if (myarray[a, b] == "have")
                {
                    
                 
                    // Control mycont = new Control(tableLayoutPanel1.Controls.ToString());
                    Control c = null;
                 
                    myarray[a, b] = null;
                    tableLayoutPanel1.Controls.Add(btn1, a, B);
                    c = this.tableLayoutPanel1.GetControlFromPosition(a, B);
              
                    tableLayoutPanel1.GetCellPosition(c);
                    if (c != null)
                    {
                        this.tableLayoutPanel1.Controls.Remove(c);
                        c = null;
              

                    }

                }


            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
        
            ((Button)sender).Dispose();
          
        }
    }
}