VB .NET Desligar o Pc

Public Class Form1

    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick

        Try

            Me.Label1.Text = Date.Today

            Me.Label2.Text = TimeOfDay.ToLongTimeString

            Me.Label6.Text = Hour(Now) & ":" & Minute(Now)

        Catch ex As Exception

        End Try

    End Sub

    Private Sub ativa()

        Try

            Me.Timer1.Enabled = True

            Me.Button1.Enabled = False

            If dtpData.Text = Me.Label1.Text And Me.Label6.Text = Me.txtHora.Text Then

                Shell("shutdown -s -f")

            End If

        Catch ex As Exception

        End Try

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Try                     

            ativa()

            MsgBox("Sistema Ativo.", MsgBoxStyle.Information)

        Catch ex As Exception

        End Try

    End Sub

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

        Try

            Me.Button1.Enabled = True

            Timer1.Enabled = False

            Me.txtHora.Clear()

            Me.dtpData.Text = Date.Today

            MsgBox("Sistema Desligado.", MsgBoxStyle.Information)

        Catch ex As Exception

        End Try

    End Sub

    Private Sub verificadata()

        Try

            If Me.dtpData.Text < Me.Label1.Text Then

                MsgBox("Não é possível selecionar esta data. É menor que a data Atual: " + Me.Label1.Text, MsgBoxStyle.Information)

                Me.dtpData.Text = Date.Today

                Exit Sub

            End If

        Catch ex As Exception

        End Try

    End Sub

    Private Sub dtpData_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles dtpData.ValueChanged

        verificadata()

    End Sub

End Class

Um abraço e att...