The user interface is not responding or updating

namespace DellOrderUP
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        // some public variables
        String Filename = "";

        // this is the browse button
        private void button1_Click(object sender, EventArgs e)
        {
            //Stream myStream = null;
            OpenFileDialog openFileDialog1 = new OpenFileDialog();

            openFileDialog1.InitialDirectory = "c:\\ ";  // *** Edit: Space added 

            openFileDialog1.Filter = "txt files (*.xls)|*.xls|All files (*.*)|*.*";
            openFileDialog1.FilterIndex = 2;
            openFileDialog1.RestoreDirectory = true;

            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                // show the user the file they selected.
                // they can only change it through the browse button.
                textBox1.Text = openFileDialog1.FileName;

                // pass the filename to public variable filename
                Filename = openFileDialog1.FileName;


                //check extension
                String Extension = openFileDialog1.FileName;

                String Check = Path.GetExtension(Extension);
                if (Check == ".xls" || Check == ".xlsx" || Check == ".xlsm")
                {
                    // enable procced button
                    button2.Enabled = true;
                }
                else
                {
                    String Error = "Sorry Only Excel Files!!!!";
                    String caption = "Excel Only";
                    MessageBox.Show(Error, caption);
                    button2.Enabled = false;
                }
            }
        }

        //private void textBox1_TextChanged(object sender, EventArgs e)
        //{}
          private void textBox1_TextChanged(object sender, EventArgs e)
          {}

        // procceed
        private void button2_Click_1(object sender, EventArgs e)
        {
            // pass the file path to OpenExcelFile
            OpenExcelFile(Filename);

            // make lable1 visbible and show state
            label1.Visible = true;

            // progress bar becomes visible
            progressBar1.Visible = true;
            
        }


        // close the program
        private void button3_Click_1(object sender, EventArgs e)
        {
            string message = "Do you want to close this program ?";
            string caption = "InventoryUploader";
            MessageBoxButtons button = MessageBoxButtons.YesNoCancel;

            DialogResult result;

            result = MessageBox.Show(this, message, caption, button);

            if (result == DialogResult.Yes)
            {
                // Closes the parent form. 
                this.Close();

            }
        }



        private void label1_Click(object sender, EventArgs e)
        {}
        private void progressBar1_Click(object sender, EventArgs e)
        {}


        // opens the file and reads the coloumns of data in
        private void OpenExcelFile(String filepath)
        {

            // Enable button 3(cancel button) and disable button2(procced button)
            button3.Enabled = true;
            button2.Enabled = false;

            Excel.Application xlApp = new Excel.Application();
            Excel.Workbook xlWorkbook = xlApp.Workbooks.Open(filepath);

            Excel._Worksheet xlWorksheet = xlWorkbook.Sheets[1];

            Excel.Range xlRange = xlWorksheet.UsedRange.Columns[37];

            // update status for the user to see
            UpdateLabel("Please Wait, reading data");
            

            System.Array myvalues = (System.Array)xlRange.Cells.Value;
            string[] strArray = myvalues.OfType<object>().Select(o => o.ToString()).ToArray();


            // get the size of strArray
            int Size_Of_strArray = strArray.Length;

            // create a new array and initilize it with the size of the previous array
            String[] FirstClean = new String[Size_Of_strArray];
            String[] SecondClean = new String[Size_Of_strArray];


            // update status for the user to see
            UpdateLabel("Sanitizing data");
            

            // in this loop, the word (exec InsertDellInventory) will be removed from each entry
            for (int i = 1; i < Size_Of_strArray - 1; i++)
            {
                FirstClean[i] = strArray[i].Remove(0, 24);

                // now remove '' and pass the data to second clean array
                SecondClean[i] = FirstClean[i].Replace("'", "");
            }

            // update progress for the user to see
                UpdateProgress(10);

            // pass the array to insert function
            BeforeInsertingIntoDB(ref SecondClean);

        }

        // update the progress bar
        private void UpdateProgress( int i) 
        {
            progressBar1.Value = i;
            this.progressBar1.Update();
            Application.DoEvents();
      
        }// update the progress

        // update the label
        private void UpdateLabel( String status) 
        {
            label1.Text = status
            this.label1.Update();
            Application.DoEvents();
      
        }// update the progress



        private void BeforeInsertingIntoDB(ref string[] data)
        {
            //update status for the user to see
            UpdateLabel("Preparing data for insertion");
   

            // create and initialize all the variables
            String PoNum = ""; String OrderNum = "";

            // get the size of the passed array
            int Size_Of_Array = data.Length;


            for (int i = 1; i < Size_Of_Array - 1; i++)
            {
                String Distribution = data[i];
                counter = i; // assign the value of i to counter

                String[] DistributionArray = Distribution.Split(',');

                PoNum = DistributionArray[0]; OrderNum = DistributionArray[1]; 
                 
                 // call the InserDataintoDB functions
                 InsertDataIntoDB(PoNum, OrderNum)

            }

            // call the update progress function
            UpdateProgress(40);

        }// End BeforeInsertingintoDB



        // insertIntoDb
        private void InsertDataIntoDB(String PoNum, String OrderNum)

        {

            ////update status for the user to see
            UpdateLabel("Opening Db connection");
            
             // call the update progress function
            UpdateProgress(20);


            String InventoryUploader = ConfigurationManager.ConnectionStrings ["DellOrderUP.Properties.Settings.InventoryUploader"].ConnectionString;
            SqlConnection con = new SqlConnection(InventoryUploader);

            try
            {
                con.Open();

                //update status for the user to see
                label1.Text = "Populating Database";
                this.label1.Update();

                // call the update progress
                UpdateProgress(30);


                SqlCommand cmd = new SqlCommand("UploadDellOrder", con);
                cmd.CommandType = CommandType.StoredProcedure;


                cmd.Parameters.Add(new SqlParameter("@ProdNum", SqlDbType.Int));
                cmd.Parameters["@ProdNum"].Value = PoNum;

                cmd.Parameters.Add(new SqlParameter("@OrderNum", SqlDbType.Int));
                cmd.Parameters["@OrderNum"].Value = OrderNum;

                
                cmd.ExecuteNonQuery();

            }
            catch (Exception e)
            {
                String caption_error_num = Convert.ToString(counter);
                String error = e.ToString();
                MessageBox.Show(error,caption_error_num);
            }
            finally
            {
                con.Close();
            }

        }