Sony PCG-NV190P - Manual (Page 143)

Troubleshooting the LCD Screen
My LCD screen is blank.
 Verify the computer is plugged into a power source and is turned on.
 Verify the power indicator on the computer is on.
 Verify the battery packs are inserted properly and are charged.
 The computer may be in LCD (Video) Standby mode. Press any key to activate the screen.
 The display mode may be set to external display mode. Press and hold the Fn key while pressing F7 several times.
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