System is running in low-graphics mode after instaling Bumblebee in my Lenovo Z570 NVIDIA gpu

I am a newable ubuntu user about a month ago.

My maschine's specs are :

Linux lenovo-Ideapad-Z570 3.11.0-19-generic #33~precise1-Ubuntu SMP Wed Mar 12 21:16:27 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

and i'm using

Ubuntu 12.04.4 LTS

after a lot of experiments to my vga card to reduse the brightness of my screen i saw a link for bumblebee https://wiki.ubuntu.com/Bumblebee#Installation and i realised that i can fix my laptop's energy problem also.
But after the installation my ubuntu the only thing that give me is a "system running in low-graphic mode".

After a lot of research i found the way to login in low res by getting in recovery menu , failsafeX, Reconf graphics , reboot and resume.

So what i have now is that my laptop can recognize the
VESA:Intel®Sandybridge Mobile Graphics and not my NVIDIA GPU.

So i went to system settings. Additional drivers and install the driver that was recomended.Reboot but the same thing. The driver was active but not in use!!!!

So after this i've done sudo fgrep nvidia * | fgrep blacklist
and i found that my NVIDIA was blacklisted!!!

I uninstalled bumblebee

$ sudo apt-get remove bumblebee
$ sudo rm bumblebee.conf

and install again Nvidia drivers but nothing again

i've tried to do this

etc/modprobe.d/nvidia-graphics-drivers.conf
but i had a command not found.

So i have only this now:

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 540M] (rev ff)

I can't undersand why Nvidia is blacklisted and why if i reinstall drivers it doesen't work.

Something more is that in bios there are only two options.
1 optimus = NVIDIA + INEL
2 UMA = Intel only

nothing works.

Is there any idea?

Thank you