Private Sub TextBox1_KeyDown(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.KeyEventArgs) _
        Handles TextBox1.KeyDown
 
        If e.KeyCode = System.Windows.Forms.Keys.Enter Then
            Dim stime As String = TextBox1.Text
            Dim time As Integer = 0
            If Integer.TryParse(stime, time) AndAlso _
                (time > 5 And time < 120) Then
                Microsoft.VisualBasic.Interaction.Shell _
                ("cmd /k shutdown /t " & CStr(time))
            Else
                Microsoft.VisualBasic.MsgBox("Falsche Eingabe")
            End If
        End If
    End Sub