This article describes how to enable the backlight for the keyboard on a Lenovo Ideapad Z400.NOTE: While this model is no longer sold by Micro Center or the manufacturer, this information may still be useful to those using this model of computer.When notebook computers comes back from sleep, hibernate or an update occurs for windows, it can keep the keyboard backlight from working.On the keyboard, the keys that are used to enable or disable the backlight is the Fn + Space bar.Hold down the FN key and then tap the Space bar. 4. This is a toggle switch that turns on and off the backlight. Turning off the backlight is useful for when you are typing in low light or an area where lighting on the keyboard is poor for viewing the letters. Note: The backlight feature is available on selected models.