This type of problem is normally hardware in nature.
Does the laptop play the Windows "welcome" sound? If you had the sound before and don't now, then you laptop may need major repairs.
Can you connect an external monitor to the laptop? Rember that you will need to activate the video port with a Function Key before you can expect to see an image on the external display. I
Try to shine a bright light at an angle on the screen when the PC is on. If you see a faint image, then your "backlight" or "inverter" is broken.
My hp laptop screen flickers between black and white patterns, and sometimes you can see a faint image of the start menu barely visible on the screen. If you leave it on for a minute you still hear the windows sound. However, I tried hooking it up to an external display, and there is no image. I am not sure what the function key is, but since there is still a faint image of the start menu I was thinking maybe there is damage to the graphics card, but I am not sure. Could you let me know?
You might have a problem with the "backlight" or the "inverter" that supplies power to the backlight. When you use an external monitor you must activate the VGA port before it will work. Look for a function key (top row) with an icon of a CRT or a key marked LCD/CRT. It's standard to press Fn + (the VGA key) at the same time. You might try Fn + (every function key) until you find the correct one.
Good Luck
I have got the same problem, I have normal picture on the VGA already changed the inverter. Shell I try to change the backlight now? I have a ZV600
Best Regards
Istvan
I would certainly take it to a repair shop to have the backlight assessed.
Regards