I want to install Debian 9 in the aforementioned laptop but I know from my experience that it will not be easy (I have tried in the past Ubuntu but only Mint worked - I suppose that there is some incompatibility with the graphics card which is NVDIA).
I found online (https://wiki.debian.org/InstallingDebianOn/Dell/Inspiron7559/stretch)
that I have to add the following line before booting (modprobe.blacklist=nouveau), but I am not sure how to do it. Any ideas?
The above method will work, but your discrete NVIDIA graphic card's capabilities cannot be used as there is no nvidia driver installed in this case. If you don't care about the power savings achieved using Optimus switching (provided by Bumblebee) and want a consistent experience where the laptop uses NVIDIA card always to output the display, there is another way.
Install Debian Stretch OS
Boot to OS and login
If the KDE session doesn't let you login, then reboot the laptop and add "nomodeset.nouveau=0" to boot options - https://askubuntu.com/questions/19486/how-do-i-add-a-kernel-boot-parameter
Enable 32 bit architecture support
$ sudo dpkg --add-architecture i386 && sudo apt update && sudo apt install -y libc6:i386
Install the following packages
$ sudo apt-get install -y linux-headers-$(uname -r) build-essential dkms pkg-config x11- xserver-utils
Download Nvidia driver for Linux-64bit
$ wget http://us.download.nvidia.com/XFree86/Linux-x86_64/410.93/NVIDIA-Linux-x86_64-410.93.run
Run the installer and follow the prompts
$ sudo ./NVIDIA-Linux-x86_64-410.93.run
If you have installed Debian with KDE environment, then the SDDM display manager is used. So do the following:
a] Get the BUS ID for your Nvidia card
$ lspci | grep 3D
b] Follow instructions on the following link to create xorg config file (Dynamic Graphics Disabled - xrandr and Display Manager Scripts) - https://wiki.debian.org/NvidiaGraphicsDrivers/Optimus
c] Follow instructions on the same page to configure SDDM startup script (Configure Simple Desktop Display Manager (SDDM)) - https://wiki.debian.org/NvidiaGraphicsDrivers/Optimus
I'm not sure if this solves all the problems you may experience at installation, but answers the question how to start up with the parameter set.
There are two steps required. The first one is after you've installed the OS and booting up, you need to boot your OS with this parameter added by hand. Then, once the OS is up, you need to change the Grub config file, so that the parameter is set automatically at bootup.
Here's a good guide for Ubuntu, which should be the same for Debian: https://askubuntu.com/a/19487/582808
In a nutshell, the first step is to edit the bootup entry and add modprobe.blacklist=nouveau. Then already in Debian, add the same to the line with GRUB_CMDLINE_LINUX_DEFAULT and then run
sudo update-grub