We need to change your password frequently from time to time from being hacked. While changing we have to enter old password and your desired new password and to confirm it we have to again enter the new password.

Program

Imports System.Data

Imports System.Data.OleDb

Public Class Form1

    Dim ConnectionString As String = System.Configuration.ConfigurationSettings.AppSettings("dsn")

    Dim con As OleDbConnection

    Dim com As OleDbCommand

    Dim oledbda As OleDbDataAdapter

    Dim ds As DataSet

    Dim str As String

    Dim up As Byte

    Private Sub btn_change_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_change.Click

        If TextBox3.Text <> TextBox2.Text Then

            MsgBox("confirm password not matching with new passsword")

            TextBox3.Focus()

            Exit Sub

        End If

        Try

            'If con.State = ConnectionState.Open Then

            '    con.Close()

            'End If

            con = New OleDbConnection(ConnectionString)

            con.Open()

            str = "select * from login"

            com = New OleDbCommand(str, con)

            Dim reader As OleDbDataReader = com.ExecuteReader

            Do While reader.Read

                If TextBox1.Text = reader("oldpwd") Then

                    up = 1

                End If

            Loop

            If up = 1 Then

                str = "update login set newpwd='" & TextBox3.Text & "' where oldpwd='" & TextBox1.Text & "'"

                com = New OleDbCommand(str, con)

                com.ExecuteNonQuery()

                MsgBox("Password changed")

            Else

                MsgBox("Please enter correct Oldpassword and Newpassword")

                TextBox1.Focus()

            End If

            reader.Close()

            con.Close()

        Catch ex As Exception

            MsgBox(ex.Message)

        End Try

        clear()

        bind()

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        clear()

    End Sub

    Sub clear()

        If Len(TextBox1.Text) = 0 & Len(TextBox2.Text) = 0 Then

            TextBox1.Text = ""

            TextBox2.Text = ""

            TextBox3.Text = ""

        Else

            TextBox3.Text = ""

            TextBox1.Clear()

            TextBox2.Clear()

            TextBox3.Clear()

            TextBox1.Focus()

            'Me.Close()

        End If

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        bind()

    End Sub

    Sub bind()

        con = New OleDbConnection(ConnectionString)

        con.Open()

        str = "select * from login"

        com = New OleDbCommand(Str, con)

        oledbda = New OleDbDataAdapter(com)

        ds = New DataSet()

        oledbda.Fill(ds, "login")

        DataGridView1.DataSource = ds

        DataGridView1.DataMember = "login"

        con.Close()

    End Sub   

End Class

Output