Identify user lock windows SO

I need to identify when the user locks up their Windows Operating System user, or the user goes into hibernation, or sleep, and takes action.

SystemEvents.PowerModeChanged += new PowerModeChangedEventHandler(OnPowerModeChanged);

private static void OnPowerModeChanged(object sender, PowerModeChangedEventArgs e)
        {
            switch (e.Mode)
            {
                case PowerModes.Resume:
                    MessageBox.Show("PowerMode: OS is resuming from suspended state");
                    break;

                case PowerModes.Suspend:
                    MessageBox.Show("PowerMode: OS is about to be suspended");
                    break;
            }
        }