Asus N55SF laptop screen blank after Windows update

Today Windows 8 (genuine version) performed a Windows update on my Asus N55SF laptop. At the time my laptop was plugged into an external Samsung TV via HDMI cable. After the installation of the update it asked me to reboot the laptop, which I did.

Ever since that reboot the built-in display of the laptop has been blank. It does turn on (I can see that the back-light goes on), but nothing appears on the screen.

I can use the laptop via external VGA port and also via external HDMI, but the internal display shows nothing, also not while booting up (bios).

What I've tried so far:

The first thing I did was uninstall the latest updates that Windows 8 had installed. This did not fix the problem.

Then I re-installed the drivers of the on-board Intel video-card & nVidia GT555M graphics card. This did not fix the problem either.

Then I removed the motherboard battery, rebooted the laptop, put the battery back, reboot the laptop again, to reset the BIOS. This did
not fix the problem either.

Then I flashed the BIOS to the same version (it already had the
lastest version). This did not fix the problem.

Then I flashed the BIOS to an older version. This did not fix the
problem.

As a last resort I formatted the laptop, and installed Windows 7 (what the laptop was made for). This did not fix the problem.

Using the function keys I can lower/upper the brightness of the screen, enable/disable the backlight, so the screen is still getting power, and working. It is simply not displaying any text/pixels.

Looking at the device manager, it lists the built-in screen as a 1024x768 LCD display. Which is wrong, as it contains a FULL HD screen this laptop. This might be the cause of the problem. Maybe Windows 8 overwrote some kind of firmware of the screen, or something else, which now causes the laptop to not detect the screen properly? Any ideas/pointers what I could try to get it working?