My screen will come on for a few seconds if i unplug an then replug the inverter ,my external monitor works and you can see the desktop very dim if you look close on the laptop,

Hope this helps.... Your monitor has an inverter issue. You know it's an inverter problem when:
1. Your monitor starts normally and displays the startup/desktop screen for a while.
2. Then it suddenly goes off, leaving a blank (black) screen or a very dim display.

To fix this black screen problem, change the inverter board (based on your monitor brand). Source(s): http://lcdmonitorrepair.annics.com

IT is the inverter. The backlights usually turn the screen orangish color before they fail.

Your backlight is probably burnt out or the inverter needs replaced. The backlight will be a pain in the rear to do so you might want to try a new / used (working) inverter in it first. Hook your laptop up to a external desktop monitor. If you computer boots up, and you can see everything on the external display, you've got an inverter or backlight issue. Shine a flashlight on the laptop screen. You'll see a very dim image of your desktop.

The Inverter is bad.

Hello !

Since an external monitor works, it is the display's backlight or inverter board.

If you were experiencing discoloration in the screen (pinkish lower light hues) before it failed, that would indicate a CCFL backlight issue. If the screen suddenly went dim on you rather than a slow degradation the inverter would be indicated.

Hope this helps.

mishwilly. If monitor will do same thing with different KNOWN GOOD pc, then monitor will need it's "switch-mode-power-supply" fixed. Could also need CCFL inverter circuit checked! Do you have warranty service? Follow the links to other web sites that you find in my FIXYA profile to read about other options open to you. 12fixlouie Read, read, read.

If the external monitor works than that is good news in a way because that means your video chip is good. Take a good close look at the screen, try to see if the desktop is actually there but just very dim. If you can make out a shadow or any part of the desktop then maybe just the video inverter has failed. Even if the inverter did fail, some lcds are so black that the desktop can't be seen regardless. In a case like this I would recommend not only getting a new screen but also the inverter as well, or replace the inverter first, it is only 15-20 dollars. Then, if the screen still doesn't come up, then change out the screen. Also make sure the data cable that attaches the motherboard to the back of the lcd is firmly seated in the socket, this can also cause a dark screen.

This could be a faulty CCFL lamp.
To determine if you have a LCD screen, inverter or video card problem, read this and follow these 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 the monitor up first then the laptop, 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.

If you have replaced the screen and the inverter, about the only thing left is the flexible cable from the monitor to the video card. I take it that the Fn+F8 makes no difference?

lamp(s) perhaps.... with an LCD monitor (the desktop kind) you can shine a lite behind it. if you can see things on the screen it's the lamps... if you can't it's something else.

Robert