How to fix Blank Screen

If your laptop screen is not working and is blank,  this can caused by any of the following reason.
· Monitor or System has no Power
· Monitor is defective
· Loose VGA/DVI Cable Connection
· Video Card Problem
· AGP/PCI-e Connector Problem / Motherboard
· System RAM Problem

However, while there may be a major problem you need to troubleshoot, here are some easy solutions to solve your problem:
1. Check the power source. While you have presumably already attempted to turn your laptop on and off, the problem may lie with your AC power adapter. Check whether the power-indicator light on the adapter on If not, your problem may lie here. However, whether or not you have a power indicator light on your adapter, consider to  plugging and unplugging it into another outlet. This may turn on your laptop and take care of your blank-screen problem.
2. Check the brightness settings. While it seems like a simple oversight, the brightness on your laptop may sometimes be turned all the way down. Thus, the screen appears to be black, off or defective, when the problem is simply that the brightness is on its lowest setting.
3. Check the laptop battery. There should be a battery indicator on the laptop. If there is no indicator, the battery itself may be the problem, and may require replacing. Take out the battery then put it back. Sometime its solve the problem.
4. Find the VGA connector and hook up your laptop to an external monitor if the above steps have not alleviated the blank-screen problem. Turn on the computer and the external monitor. Does the external monitor light up? If so, the blank screen is likely due to a video subset problem/LCD problem in your laptop.
5. Check the RAM. Sometime RAM problem can result in blank screen.

If the problem not solved, Consider to taking the laptop to a professional repairman or sending it off to the manufacturer is recommended.

SRC:
http://www.ehow.com/how_4844299_fix-blank-screen-laptop.html
http://www.online-tech-tips.com/computer-tips/blank-display/