Was there any light on the built in lcd panel? Did you try an external? If so what was the result? If you have a very bright flash light, you can shine it on the lcd panel and see if any picture is actually there. I am not certain if your model has an inverter or if it is a LED back lit LCD, if it has an inverter, it is possible this component failed. The inverter provides high voltage current to run the CCFL backlight. If it fails the screen may appear black but will still have an image that a bright light may help you see. If there is a back light but no image, it is possible your lcd panel has a problem, or your main board has a problem.
If there is no picture at all including on an external monitor, the next thing I would do is remove all components that are not required to get the computer to fully post. Hard drives, webcam, keyboard, mouse, wireless mini pci-e card etc... This would require taking the computer apart. Any component can cause a post failure. You should leave 1 stick of ram in, the built in monitor hooked up to the main board, the cpu and cpu cooler/fan installed and then only use the power adapter (leave the battery disconnected).
One thing I should mention now: ALWAYS disconnect all power (battery and power adapter) from a computer before removing any components. If you leave the battery in when removing components, you can cause permanent damage by shorting pins.