Make sure the brightness and contrast controls are adjusted correctly.

An external display may be selected as the display output.

Press the Fn+F7 keys several times to select your desired display output, and then press the Enter key.

If you are using an external display, make sure it is plugged into an AC outlet and is on. Make sure the brightness and contrast controls are adjusted correctly.

Refer to the manual that came with your display for information on how to change the settings.

Press the Alt+F4 keys several times to close the app window.

An app error may have occurred.

If you wait for a while and the computer screen remains blank, restart your VAIO computer by following the procedures below in order. Note that following these procedures may cause working data to become corrupted.

• Disconnect all peripheral devices, such as a printer or a USB device, and your VAIO computer from the network, if any.

• Press and hold down the(Power) button for more than four seconds and make sure the power indicator light is off. Then, turn on your VAIO computer again.

If the problem persists, press and hold down the(Power) button for more than four seconds and make sure the power indicator light is off. Disconnect all cables connected to your VAIO computer, such as the AC adapter, remove the battery pack, and wait about five minutes. Then, put all cables, peripheral devices, and the battery pack back in place and turn on the computer again.

If an extra memory module is not installed properly, your VAIO computer may not turn on.

Use of memory modules not specified by Sony or improper installation of memory modules may cause the computer to fail to boot or to become unstable. In such a case, reinstall the memory module.

If you use a memory module other than the Sony branded memory module, contact the sales dealer or the manufacturer of the memory module.

If you bring your VAIO computer directly from a cold location to a warm one, or use it in a high humidity location, moisture may condense inside the computer.

In such a case, allow at least one hour before turning on the computer.

Do not use the computer in a high humidity location (a relative humidity of more than 80 %), as it may cause the computer to malfunction.