This was a long journey ... an answer in progress … and now finally … here is the answer !
What you want is - more or less – a complete instruction on how to install Ubuntu alongside Windows. Please stay tuned - I will give you all advice necessary to get everything running!
So let's start …
First boot into your Windows installation and disable hibernation and Fast Boot.
Disable hibernation by opening command prompt as administrator and execute:
powercfg /h off
To disable Fast Boot open Control Panel (the old version - not the modern design),
select the Energy Settings, enable show hidden settings and uncheck Fast Boot.
Shut down the machine completely – do NOT reboot!
Boot from Ubuntu installation media and highlight Try Ubuntu without installing.
Press 'e' and add nouveau.modeset=0 to the end of the linux line, then press F10.
On the live desktop press the Windows key and type GParted into the search field.
Open GParted and reduce the Windows partition if there is no unallocated space.
Create two new partitions and format one with ext4 - the other with linux-swap.
Now start the Ubuntu installer from the desktop and choose Something else.
Select the ext4 partition you have created before and choose /
as mount point.
Select the same disk on which Windows is installed to install the bootloader to.
Start the Ubuntu installation process and when everything is completed, restart the computer.
Boot into BIOS and select Ubuntu in UEFI settings to be the default operating system to boot.
Now you are able to select the operating system you want to boot from the GRUB boot menu.
Boot Ubuntu installation and first of all install the most recent stable NVIDIA graphics drivers.
When the login screen appears press keys Ctrl+Alt+F1.
Enter your user name and the password and then execute:
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update
sudo apt-get install nvidia-355 nvidia-prime
sudo reboot
Now you can boot into the desktop of the Ubuntu installation and start to customizing …
Note:
If you want to install Ubuntu to another disk, you can do so even if it is not recommended.
Important – boot loader has to be installed to the same disk where Windows is installed.