if (!txtUsername.Equals(null) && !txtPassword.Equals(null))
            {
                string constring = @"Provider = Microsoft.ACE.OLEDB.12.0; Data Source = " + System.Environment.CurrentDirectory + "../../../res/Coursework.accdb";
                string cmdText = "select Count(*) from tblUsers where username=? and password=?";
                using (OleDbConnection con = new OleDbConnection(constring))
                using (OleDbCommand cmd = new OleDbCommand(cmdText, con))
                {
                    con.Open();
                    cmd.Parameters.AddWithValue("@p1", txtUsername.Text);
                    cmd.Parameters.AddWithValue("@p2", txtPassword.Text);
                    int result = (int)cmd.ExecuteScalar();

                    if (result > 0)
                    {
                        if (true /* is admin*/) return; //show database edit form
                        else return; //show database add form
                    }
                    else
                        MessageBox.Show("Invalid Login, Please Re-Enter.");
                }
            }