SSD-Optimierung Was mach ich hier falsch?

Public Class Form1

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

        'Defragmentierung ausschalten  
        Dim regKey As Microsoft.Win32.RegistryKey
        regKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey("SYSTEM\CurrentControlSet\Services\defragsvc", True)  
        regKey.SetValue("Start", 4)  
        regKey.Close()

        'Indexierung ausschalten  
        regKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey("SYSTEM\CurrentControlSet\Services\WSearch", True)  
        regKey.SetValue("Start", 4)  
        regKey.Close()

        'SuperFetch ausschalten  
        regKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey("SYSTEM\CurrentControlSet\Services\SysMain", True)  
        regKey.SetValue("Start", 4)  
        regKey.Close()

        'PreFetch ausschalten  
        regKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey("SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters", True)  
        regKey.SetValue("EnablePrefetcher", 0)  
        regKey.SetValue("EnableSuperfetch", 0)  
        regKey.Close()

        'Boot-Time Defragmentierung deaktivieren  
        regKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey("SOFTWARE\Microsoft\Dfrg\BootOptimizeFunction", True)  
        regKey.SetValue("Enable", "N")  
        regKey.Close()


        'Ruhezustand ausschalten  
        Shell("powercfg -H off")  

        Box.Text = "Bitte neu starten"  

    End Sub
End Class

System.NullReferenceException