BSOD STOP: ntoskrnl.exe+74ec0: error 0x0000007F

I have a Lenovo Z570 (i5-2450m + 6GB ram + NVidia gt520m) + Windows 7 Ultimate

I get BSOD when I try to watch a youtube video in Firefox.

I have to say that this laptop has a physical switch to turn on and of Nvidia. Otherwise it uses Intel HD Grapics.
During the BSOD Nvidia was disabled.

I tried to install the original driver for HD Grapics but I still got BSOD.




Now I turned on Nvidia and in Nvidia Control Panel I set Firefox to work with the High Performance Graphics Device.
Since then everything is fine.

But if I always use Nvidia the battery won't last long. So I want to use HD Graphics without BSOD.

I uploaded the SF Diagnostic Tool Results.
Can someone figure out the cause for the BSOD?

(I read other posts with similar error. I've never had any other antivirus soft, beside ESET Smart Security)

I don't quite remember. Perhaps KM activator or Loader by Daz.

Anyway, since I reinstalled some drivers and using optimus nonstop (nVidia and Intel HD Graphics), I haven't experienced any BSOD.