Backlight issues Asus X54H (solved)

A friend is running this elderly piece of Asus failure (I did some research, it seems that Asus made a piece of overheating disapointment here). Had lots of problems crawling through the malware and uwp (unwanted programms) and now after installing the correct drivers for the GPU (HD 7470M), the backlight stops after the Win7 logo is displayed (correctly).

Solutions that did not work:
- Using a flashlight you can see the screen displaying the login menu.
- Restoring old drivers
- Re-installing new drivers again
- key-combos to turn the backlight back on or increase brightnes
Solutions mentioned in this thread not working:
- uninstalling newly installed software
- restoring Avast! or/and Avira
- removed MS Essentials

Steps leading in the right directions:
- Running it in safemode. Backlight stays on, I can work
- Running Kaspersky Rescue Disc (running right now, same result as Safemode. Scanning for anything I might have missed).

Changes made before it stopped working (in order):
- Installed Malwarebytes Antimalware
- unistalled Avast! and Avira
- updated/installed drivers for: gpu, chipset, cardreader
- installed Microsoft secruity essentials
- removed ~300 malicious pieces of data
- rebooted <- and here it stopped working

Asus X54H (2011)
Intel Pentium B960 at 2.2Ghz (stock)
Original config with HDD and CD/DVD writer
Windows 7 64bit

Try running it in safe mode. See if the display works then.

If not, can you do a system restore back to before you installed Malwarebytes? Then reboot after each of the things you did to narrow down the change that caused this. When it happens again, the last thing you did is most likely the cause, or at least related to the cause. If you don't get the display after restoring though, you'll have to look deeper. Since you can't see the image when shining a light, it's not the inverter.

What model and year laptop is this?

@HK_47 Okay, I tried removing different software or restoring older ones. Safemode is working as KasperskyRescueDisc. I get a nice display as if nothing was wrong.
Might have been my not to great english but the screen is showing something, it is really just the backlight not working when booting into normal Windows. I might try installing some sort of Linux or saving everything thats on there and installing a fresh version of Win7.
It is a 2011 one

Hold on, don't jump the gun.

Boot in safe mode and check your display settings. Set your resolution to the smallest setting, usually 800x600, but it depends. Change color quality to something like 256 or lower. Then in Adavanced Settings under the Monitor tab, make sure the refresh rate is set to 60 Hz. Reboot and see if it works now.

@HK_47 Thanks for your time but it looks like I need to take the reinstall route.
Tomorrw I will decide if I like to spend more than the ~6 hours I invested already or go the simple way.
Edit: For some reason and god knows why, it startet working again after I put in a Windows7 cd to set it up. It rebooted into the login screen and now it is all working again.

Hahaha, computers...such fickle devices. Glad you're up and running.

Thanks for your help.