Can't change resolution!

Completely remove all the NVIDIA software you have installed and reinstall the NVIDIA drivers.
Because you have the 361 drivers installed - you do not need to add the GPU Drivers PPA again.

Highlight the Ubuntu menu entry and press the E key.
Add nouveau.modeset=0 to the end of the linux line.
Press the F10 key to boot into the Ubuntu system.

Open a terminal and execute :

sudo apt-get purge nvidia*  
sudo reboot  

After the restart ...

Highlight the Ubuntu menu entry and press the E key.
Add nouveau.modeset=0 to the end of the linux line.
Press the F10 key to boot into the Ubuntu system.

Open a terminal and execute :

sudo apt-get update
sudo apt-get install nvidia-361 nvidia-prime
sudo reboot