Sheet1$ does not exist error coming when writing to excel file using oledb

private void btn_submit_Click(object sender, EventArgs e)
       {
           try
           {

               string name = textBox1.Text;
               string filepath="D://"+name;

               System.Data.OleDb.OleDbConnection MyConnection;
               System.Data.OleDb.OleDbCommand myCommand = new System.Data.OleDb.OleDbCommand();
               string sql = null;
               MyConnection = new System.Data.OleDb.OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0;Data Source="+filepath+".xls;Extended Properties=Excel 8.0;");
               MyConnection.Open();
               myCommand.Connection = MyConnection;
               sql = "Insert into [Sheet1$] (name,email) values('"+textBox1.Text+"','"+textBox2.Text+"')";
               myCommand.CommandText = sql;
               myCommand.ExecuteNonQuery();
               MyConnection.Close();
           }
           catch (Exception ex)
           {
               MessageBox.Show(ex.ToString());
           }
       }