LCD Screen has has no light to it anymore

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

Look at the LCD screen very closely and check if you can see a faint image on the screen. It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

Yes, you're back light has failed.

Flickering, always cause by LCD cable. Change it at any computer shop or service center and its not so expensive

Some Windows start up file is corrupted. Repairing the Operating System will solve the problem.

The screen is just defective. There is 2 components in LCD screen.
1. the LCD
2, The back light witch is like a big neon that makes the screen bright.

In your case the LCD works since you can see the screen if you get close enough, but the back light is dead.
You can fix this by basically replacing the screen.

its in neither its a seperate circuit board that connects the screen to the motherboard and its called an inverter
http://www.laptoprepair.co.uk/how-to-repair-backlight-inverter.htm
you will need the correct inverter board for your laptop and will need to find the relevant instructions on how to replace / repair it and take care and have lots of patience and persistence as it can be fiddly

It should change by pressing the DISP button when in shooting mode.