|Have you, or is it possible someone else who had access to this computer...|
- dropped it, or dropped anything on it, or otherwise exposed it to a physical jolt ?
- spilled liquid on it, or sprayed it with liquid, or exposed it to liquid such as rain ?
Since the video last worked properly all the time, has there been a power failure event that happened while the AC adapter was plugged in ?
Those things are the most frequent reasons something inside the laptop has been damaged.
"... when we open it all the lights are on bu screen was plain in black.. we can still do the f12 and f8 after that nothing happens.."
Searching the web with toshiba satellite M200 finds that it probably first came out in early 2008 or late 2007 - your laptop may be that old. If it has been used constantly since it was new, it's common for you to have video problems with a laptop that has been used a lot.
You should ALWAYS have normal video while booting before Windows loads. If you don't, yet the leds on it are lighting up fine, there is probably something wrong with the built in display or with the wiring between the display and the video adapter.
If you DO NOT always have normal video while bootong before Windows loads. try connecting an external monitor.
Laptop no video (or video problems), and battery, AC adapter, power jack T shooting.
See response 1:
DO NOT plug in or unplug a monitor's video cable into / from a video port while the computer is running. Doing so can damage the monitor's circuits and/or the video adapter's circuits.
Some laptops will display on an external monitor without you having to do anything.
If you get no video on an external monitor, some laptops have a key combo that you must press to toggle the display to external video only / built in display video only / sometimes both - see the Owner's or User's manual for the model.