Dell XPS L702X brightness issue

Dear support,

I recently aquired a Dell XPS L702X. I'm having issues with adjusting the brightness (it's set really high, it's hurting my eyes!). Adjusting it doesn't seem to have any effect, no matter if I do it through Fn + F4/F5 or from Control Panel -> Display -> Adjust Brightness. The only workaround I could find is to use nVidia Control Panel, as shown below, but even at 0 brightness, it's still intense for the eye, I don't think that setting is really changing the actual screen brightness.

I installed the following drivers/apps from your site:

• Intel Centrino Advanced-N 6200 Wireless-N 1000 Ultimate-N 6300 Driver (25).exe
• nVidia N12E-GE-B ( GT555M) nVidia N12E-GE-B(LP)-GT 550M (27).exe
• nVidia Stereoscopic 3D USB Controller (14).exe
• ST Microelectronics DE351DL Motion Sensor.exe
• Quanta H.264 integrate webcam (24).exe
• Synaptics Synaptics TouchPad.exe
• Renesas USB3.0 Host Controller Driver (35).exe
• Realtek RTL8111EL Driver.exe
• Intel Huron River (HM67) (26).exe
• Intel Management Engine Interface.exe
• Dell QuickSet.exe
• BIOS A10.exe

I read on forums and people were saying that the latest BIOS upgrade should fix this. Unfortunately it didn't, I installed the latest from your website as shown in that list.

Please advise!

Thank you!