After turnin gon the screen will stay dark - Sony VAIO VGN-FS840/W Notebook

Hi , I think your laptop brightness settings had been changed. So try this to increase and reduce the brightness , contrast. Select start-> control panel -> appearance & personalization -> display . There you will have options like Adjust brightness , Adjust resolution etc., on the left side of your window. You may adjust in this way.

Then You might have an Inverter Problem or the back light lamps are going bad.

On ALL Panasonic Toughbook Models,
if the screen stays dark I would shut-off the
Toughbook and connect an external monitor
to the VGA port (15-pin female connector),
which is usually BLUE in color.

Make sure the monitor is ON first, then
turn ON the Toughbook.

If the monitor comes on then your problem
is the backlight or possibly the inverter of the
screen.

If no image is shown on the external monitor
and the screen stays dark and you cannot
hear any startup (ie. Windows) sound, then
your video card may be defective. Very few
Toughbooks fail this way since they are
normally very very relaible but it can happen.

Good Luck
Regards,
Richard - Montreal Based
Panasonic Canada Toughbook Authorized Dealer since 1989

check for vacuum leaks,check battery and connection,fuel filter,stareter.

Not even beeping? Hard to tell from such little info. HDD doesn't work, CPU stays cold, that would indicate a motherboard problem, but then it would beep most of the times. It can be a a problem with your screen, but that doesn't add upp with the HDD, and the CPU staying cool (bye the way, how do you know that?)
I think you should take it to someone who can take a closer look on it.

You could have a defective screen - a defective inverter or a CCFL lamp.
To determine if you have a LCD screen or video card problem, read this and follow the instructions.

Defective CCFL backlight, it may have the following symptom:

• Screen flashs on red/pink and off.
• Picture stays on in red and slowly be come normal.
• Picture flickering with dim display or appear black.
• Picture flickering on and off.

All these symptoms indicate that the LCD backlight lamp (CCFL Lamp) has reached the end of the life and all you need to do is replacing the CCFL lamp

Connect an external monitor to your laptop and power it up, if you see the normal Windows images then the video card and laptop is OK and the problem is definitely the backlight.

Dim image and/or dark display on the laptop's LCD screen indicates a faulty LCD backlight and it could be the inverter that supplies high voltage to the CCFL lamp or it is the CCLF lamp is nearly burnt out or burnt out, most likely this is the case.
The inverter can be replaced easily but the CCLF lamp is more time consuming and requires soldering skills.
Check out www.lcdparts.net for parts, repair service and DIY info.

OMG MINES TOO, den a few weeks later, it stays blk,it only works somtime wen i keep [pressing] random buttons but now it stays pitch blk , :( but as for now since ur phone is actin like tht before it gets worst, reboot ur phone by turnin it off, then hold on to the power/end button nd da home button at the same time for at least 15 sec. then a rebooting sign will come on, tht shud fix ur phone for the mean time .

try to look at its circuit board and look for some cold solder

Please change display

Have u tried re-installing the video drivers?