Uninstalling Ubuntu 14.04, and installing Ubuntu 18.04 in its' place [duplicate]

Question

How do I go about uninstalling Ubuntu 14.04 (such that all of my Python and path issues will be removed), and then install the newest version (Ubuntu 18.04) ... without using the typical upgrade procedure?

I would like to preserve my dual boot (Ubuntu + Windows), and I definitely don't want anything to happen to Windows (even though it's backed up too). My laptop has already been partitioned by someone else when I originally bought it new, so I don't think I have to go through the process or creating a new partition from Windows?

As always, any help with this would be much appreciated!

Context for why I want to do this, and information about my system:

Recently I've created a mess of my Ubuntu 14.04 packages. For more details, see here.

The gist of it is I someone broken Python, among other important system programs, which is problematic because to install/reinstall/uninstall anything (including Python) I need a working Python program.

I run a dual boot, with Windows 8 being the other partition. 64 bits. This configuration has always been relatively good, with some minor bugs here and there.

A few people have kindly tried to help me parse out and solve the problem, and perhaps we're making progress (I don't think I know enough to see the big picture), but I suspect it will take a while to unravel all of the issues + install Jupyter noebook properly afterwards (the initial installation of this is when the problems began).

If you have any suggestions for the problem at hand, I'm happy to hear them!

I didn't want to uninstall Ubuntu 14.04 and reinstall another version of Ubuntu initially, someone else installed my dual boot with Ubuntu + Windows to begin with, so it seemed like a daunting task. With that said, it seems like it might be the quickest solution to my current dilemma (other than maybe installing Anaconda/Python/Jupyter on Windows?).

The descriptions on here and here are not an option, because although I'm essentially upgrading, I'm unable to do it using my broken Ubuntu 14.04 installation. For instance, update manager is not working.

I have already backed up my files on both my Ubuntu and Windows to an external drive. I don't have a terribly large amount of programs on Ubuntu to loose (Chrome, Mozilla, Thunderbird mail, etc.), so it wouldn't be that inconvenient to have to reinstall them.

Answer 1

Following Kulfy's instructions, I went here and here. My process differed a bit from the one here, so I'll give the slight differences below.

On Windows, I downloaded the Ubuntu 18.04 ISO file.

Backed up and removed all files from a (SanDisk) 16 GB USB drive. Created a bootable USB following the instructions here, which required me to download/install/use the free program Rufus. Checked that Rufus worked properly (i.e., if files on the USB were correct) - it did.

Then I rebooted my system, with the USB drive plugged in.

When I got to step #5 here, my options were a bit different. In my OS boot menu (four options: Debian GNU/Linux, Advanced options for Debian GNU/Linux, Windows Boot Manager, and System Setup), I chose "System Setup".

In here, I originally explored "F10 BIOS Setup", which proved not to be useful. Instead, I chose "F9 Boot Device Options", which loaded a menu with three options: OS Boot Manager (which just returned me to the original OS boot menu of four options), USB Hard Drive(UEFI) - San Disk, and Boot from EFI File. I chose the second option of those three. This gave me the options that step #6 here described, even though I was using UEFI. I chose "Try Ubuntu without installing" from here, then installed Ubuntu from within the Ubuntu start up.

A few more steps varied from this tutorial afterwards, owing to my having a Ubuntu 14.04 partition already installed. It gave me the option to completed erase and overwrite the Ubuntu 14.04 with the new Ubuntu 18.04 installation, which I doubled checked was the correct one, then went with it. From here, I followed the rest of the necessary instructions found on the other tutorial, excluding step #7's suggestion that I "may safely disregard the second option 'Install this third-party software'". I opted to let Ubuntu install all of this stuff, updates, etc. etc..

Somewhere in here I rebooted my system, as recommended by Ubuntu. When I did so, the OS boot menu's four options changed to: Ubuntu, Advanced options for Ubuntu, Windows Boot Manager, and System Setup, and the screen behind these options were now purple instead of blue.

After setting the Ubuntu 18.04 system up, both my Ubuntu and Windows boots are working (minus the bug described below for Ubuntu).

Initial Set-up Bug

There DOES seem to be one bug with my new Ubuntu 18.04 setup, in that the screen will go black for maybe 2-3 seconds, then, the whole displace will rotate horizontally. With my mouse cursor, "up" goes horizontally towards the top of this rotated screen. Rebooting the system brings me back to the normal "up" is "up" display, but then after a short time the screen goes black, and repeats. Have tried rebooting twice now, same results.

Will look for a solution, and if I cannot find one, will post a new, separate AskUbuntu question.

Update

Found the solution, it is here. This worked for Ubuntu 18.04, on a HP 17 Pavilion Notebook. I first titled my laptop until it oriented in the correct, upwards landscape. Then I locked the titled ability with the menu on the top right. Then in terminal I entered:

gsettings set org.gnome.settings-daemon.plugins.orientation active false