When you press your power button on your laptop and the LCD screen just stays black. What is the problem?
Possible problem can be the on-board video chip or Video Card.
Possible problem can be the power inverter.
Possible problem can be the back light of the LCD screen.
Bad LCD Cable Connections
On-board VIDEO CHIP or Video Card BAD
First let's look at the possibility that your video chip on your motherboard is bad. You can also have a separate video card instead of on-board video chip.
If you press the power button on your laptop and you just get a blank screen, then you need to do a couple of checks to see just what the problem might be.
If the LED lights are on and you hear the fan in the laptop running and hard drive working but there is no video, that usually means the video chip on the motherboard has gone bad. This can be repaired by re-flowing the video chip. You will have to find a good repair tech that knows what he is doing for this repair. It might cost in the neighborhood of $150.00 for this repair.
Plug a external monitor to the laptop and see if you have any video. If you see video on your external monitor then your video is OK.
Power Inverter / Backlight BAD
When your power inverter is bad or the back light is bad, you can usually see a faint image on the LCD screen.
If your video displays on the external monitor then your LCD screen has a problem. Either your power inverter is bad or your LCD backlight has gone bad.
Check that your power inverter plug it seated properly. Without a tester to hook to the inverter or back light (CCFL) there is a general guideline you can use:
If this happen all the sudden that your screen just went black it is most likely it is the inverter.
If your LCD screen has been geting light and dark or colors have been getting off for a while it is your back light (CCFL).
You can actually have the light replaced but it is a tedious process and it is probably better and cheaper to find a new LCD screen on eBay.
Sometimes memory modules can do this. If you have extra good memory you can swap out and see if it woks. If you have an extra laptop around that usees the same memory you can put the memory modules in question in the extra laptop and use memtest software to test it.
I have seen loose cables and improperly seated cables do this as well.
Check the connections at the motherboard and back of lcd screen to make sure they are seated properly.
If your onboard video chip has gone bad on your motherboard, you can have it repaired at a reasonable cost compared to having to buy a new motherboard. This repair will have to be done by a good repair technician and that will be cheaper than a new motherboard. If your video card is bad then you can replace it.
If your inverter or backlight is bad and you have taken apart a laptop before, you can change the power inverter or LCD screen yourself, but only attempt this if you are sure you can take apart the laptop without breaking anything.
If you can take apart your laptop and check the cables you can save your self some money and time.