Acer Aspire 2920z Black screen

One day I can be patient Acer Aspire 2920z, quite a headache is due to a strange illness following further information:

Symptoms:
Power and battery leds blink as soon as I plug adapter
Backlight screen does not light up
when the battery is removed, the result is the same
after browsing there here, finally getting advice like this:
Unplug and remove the battery. Then hold the power button pressed for about 1 minute to discharge static laptop. (O ow ,,, it still be dead, only the lights are flashing)

Dead motherboard. (Hmmmm .... I'm not sure!)
There was a short circuit in the display cable. (Then I Tried external monitor .... it is still the same.)
Power adapter you die and have to replace a new one, (oooo yaaaa .... this does not look like a scar ..)
There is something wrong with the electrical conductors. (I'm almost sure that this is a problem but it does not ...)

A friend told me he had the same problem and he managed to deal with flashing the BIOS. Do not believe it at first, but then that's what I did.
Finally I decided to back the flash BIOS.
first of all I Download the latest BIOS from http://support.acer-euro.com/drivers/downloads.html and not the new site (that includes the ancient versions and no DOS utilities ...)
Download UNetbootin.
Create FreeDOS usb with unetbootin
Copy and paste all the files from the zip you downloaded from Acer to a bootable usb stick just created
Boot your laptop from usb stick and select option 5 when the menu appears FreeDOS
Type a usb stick drive letter (eg F :)
type "dir" to see whether you are in the right drive (you will see the inserted file)
if true, type "phlash16 / x / s / mode = 3 CLD - 114.WPH" to flash the BIOS
wait a few minutes and
Alhamdulillah succeed to ........