Updating The Database

Hi All:


Appreciate your efforts in answering queries of so many newbees!
I hope to find answering my query..
I
have created a logon screen to which i have also given the option of
changing the password ... Now below is the code for updating the new
password given by the user ....
Imports System.Data.SqlClient 
    Dim con As New SqlConnection("server=sys2;initial catalog=kris;integrated security=SSPI")
    Dim cmd As New SqlCommand("select * from u_login", con) 
    Dim dr As SqlDataReader

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubmit.Click
        con.Open()
        dr = cmd.ExecuteReader
        While dr.Read()

            If dr(0) = txtEmail.Text And dr(1) = txtoldpwd.Text Then
                Dim NewPwdStr As String = txtnewpwd.Text
                Dim OldPwdStr As String = txtoldpwd.Text

                Dim sqlstr As String = "Update U_Login set pwd = ('" & NewPwdStr & "') Where pwd = '" & OldPwdStr & "'"
                Dim cmd1 As New SqlCommand("sqlstr", con)
             
                          cmd1.ExecuteNonQuery()
                Response.Write(" Password Changed ... Please login again")

            End If
        End While

        dr.Close()
        con.Close()

    End Sub

The above code although doesnt
throw any error however it shows a blank screen and doesnt even update
the new password. Can you plz help me understand what could possibly be
wrong in my code n why is that am getting the blank screen.
 
Your help will be highly appreciated!
Thanks,
Brandy