hi i am new to c# and wondering if you could help me solve the problem to my login function for my website thanks

Code:
 protected void btnlogin_Click(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=CWsystem.mdb");
          //  OleDbConnection con = new OleDbConnection(ConfigurationManager.ConnectionStrings["CWsystem.mdb"].ConnectionString);
            con.Open();
            string cmdStr="select count(*) from Person where UserID='" + txtusername.Text + "'";
            OleDbCommand Checkuser=new OleDbCommand(cmdStr, con);
            int temp = Convert.ToInt32(Checkuser.ExecuteScalar().ToString());
            if(temp== 1)
            {
                    string cmdStr2="Select Password from Person where username='" + txtusername.Text + "'";
                OleDbCommand pass=new OleDbCommand(cmdStr2, con);
                string password=pass.ExecuteScalar().ToString();
                con.Close();

                if(password == txtpassword.Text)
                {
                    Session["New"] = txtusername.Text;
                    Response.Redirect("university.aspx");
                }
                else
                {
                    Label1.Visible = true;
                    Label1.Text = "invalid password";
                }
            }
                else
                {
                    Label1.Visible = true;
                    Label1.Text = "invalid password";
                }

            }

        protected void txtpassword_TextChanged(object sender, EventArgs e)
        {

        }
        }
    }