Ubuntu 16.04 nvidia drivers don't work

I've just installed a new ubuntu 16.04 ,
fresh install clean , logged in the first and only thing i did is selecting the proprietary driver 361 for nvidia , rebooted the machine .
anfter rebooting i can login but unity isn't showing , i can still right click though and open terminal , tried many answers:
link1
link2

did not help , i got frustrated , booted into usb and freshly installed it again, this time i tried 340 drivers same problem .
i mean this is 16.04 LTS for gods sake .
i have dual grahpic cards nvidia gt 740m , intel built on ASUS laptop .

output of grep "EE\|WW" /var/log/Xorg.0.log :

(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    23.758] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[    23.758] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
[    23.758] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
[    23.758] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
[    23.758] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
[    23.761] (WW) "glamoregl" will not be loaded unless you've specified it to be loaded elsewhere.
[    25.323] (WW) Unresolved symbol: fbGetGCPrivateKey
[    25.448] (WW) NVIDIA(0): Unable to get display device for DPI computation.
[    25.613] (WW) modeset(G0): Option "AllowEmptyInitialConfiguration" is not used
[    25.613] (WW) modeset(G0): Option "IgnoreDisplayDevices" is not used
[    25.902] (EE) NVIDIA(0): Failed to initiate mode change.
[    25.902] (EE) NVIDIA(0): Failed to complete mode change
[    26.214] (WW) evdev: SteelSeries Sensei Raw Gaming Mouse: ignoring absolute axes.
[    26.216] (WW) evdev: SteelSeries SteelSeries Apex Raw Gaming Keyboard: ignoring absolute axes.
[    26.272] (II) XINPUT: Adding extended input device "USBest Technology SiS HID Touch Controller" (type: TOUCHSCREEN, id 16)

full log file LOG

xorg.conf file :

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "nvidia"
    Inactive "intel"
EndSection
Section "Device"
    Identifier "intel"
    Driver "modesetting"
    BusID "PCI:0@0:2:0"
    Option "AccelMethod" "None"
EndSection
Section "Screen"
    Identifier "intel"
    Device "intel"
EndSection
Section "Device"
    Identifier "nvidia"
    Driver "nvidia"
    BusID "PCI:4@0:0:0"
    Option "ConstrainCursor" "off"
EndSection
Section "Screen"
    Identifier "nvidia"
    Device "nvidia"
    Option "AllowEmptyInitialConfiguration" "on"
    Option "IgnoreDisplayDevices" "CRT"
EndSection

Found the solution (this time for real),
i decided to be an ubuntu expert , so i went to google and typed :

debug ubuntu

then it gave me the page Debug and i selected unity .
in some part i needed to do :

$ unity --advanced-debug
GNU gdb (GDB) 7.2-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-linux-gnu".
For bug reporting instructions, please see:

...
(gdb) set logging file unity.log
(gdb) set logging on
(gdb) b _exit
Function "_exit" not defined.
Make breakpoint pending on future shared library load? (y or [n])
[Answer yes (y)]
(gdb) run
[ and when compiz/unity crash, do...]
(gdb) bt full
[ then CTRL-D or re-run compiz to continue working ]
(gdb) run

after running this i noticed the error :
compiz (core) - Error: Plugin 'opengl' not loaded.

i searched for this error on google and it gave me this thread Unity missing? Can't see top or side panels , the answer here works .