Usually there is an inverter for the CCFL backlight PS. If it is not working there will be no visible display.
Quick check for backlight problems is to shine a bright torch at the screen and look for an image "front lit". If a "front lit" image is present then fault find the inverter circuit.
They can be a quite simple free running RC push-pull primary or a more complex IC controlled type.
Another check is to hold a scope probe near the transformer and look for ~20 KHz oscillation.