I can't remove python. I'm not kidding, it doesn't get uninstalled.

[Gribouillis]

oh you mean entire programs? Not just packages they depend on?

I mean that apt removed programs that depend on python to run. They won't be reinstalled if you attempt something like "reinstalling python", which by the way is probably unnecessary because in the end you still have python.

It is not difficult to reinstall ubuntu

1. Save your personal files on an external hard drive before you do anything else.
   
2. Burn a bootable DVD with the .iso image of Ubuntu 18.04 downloaded from the ubuntu website. They say that you can also create a bootable USB key instead of a DVD but usually I don't have much success with this.
   
3. Reboot the computer on the DVD (make sure the computer is connected to the internet) and follow the installation instructions.
   
4. Remove the DVD, reboot the computer and do sudo apt update and then sudo apt upgrade in a terminal.
   
5. Reboot and enjoy a fresh install of Ubuntu.