Removed Python 3 and now Ubuntu Software Center, terminal and other applications don't work

Solution 1:

1. Open a text-only virtual console by pressing the keyboard shortcut Ctrl + Alt + F3.

2. At the login: prompt type your username and press Enter.

3. At the Password: prompt type your user password and press Enter.

4. Reinstall the default Python 3 version by running the following command:

   sudo apt install python3-all
   

5. Switch out of the virtual console and return to your desktop environment by pressing the keyboard shortcut Ctrl+Alt+F7. In Ubuntu 17.10 and later press the keyboard shortcut Ctrl+Alt+F2 to exit from the virtual console.

After you have installed the default Python 3 version, you need to get back your default Ubuntu desktop system. In order to avoid messing something up, do it in the following order:

1. First install the terminal from a virtual console using the command: sudo apt update && sudo apt install gnome-terminal. If you can't install gnome-terminal at all, skip this step and go to step 2.

2. Return to your desktop and open the terminal using the keyboard shortcut Ctrl + Alt + T. In Ubuntu 14.04 and earlier from the terminal install the Ubuntu Software Center using the command:

   sudo apt install software-center
   

   In Ubuntu 16.04 and later run this command instead to reinstall the default Software application:

   sudo apt install gnome-software
   

   If you still can't open the terminal, run the same command from a virtual console instead. If you can't install the default software application at all, skip this step and go to step 3.

3. Open the terminal and try to open the Ubuntu Software Center from the terminal by running the appropriate command, either software-center or gnome-software. From the Ubuntu Software Center install the Ubuntu desktop system or else open the terminal (or a virtual console) and install the Ubuntu desktop system by running the command: sudo apt update && sudo apt install ubuntu-desktop.

Solution 2:

This is what I did:

Press Ctrl+Alt+F1 and login.

Run this command:

sudo apt-get remove python/python3

Reboot

Press Ctrl+Alt+F1 and login.

Run these commands:

sudo apt-get install python3
sudo apt-get install python
sudo apt-get install ubuntu-desktop

Reboot

Done!

Solution 3:

To fix the problems with your system you just need to re-install python 3.3.

If you ran for example: sudo apt-get remove python3

You can reverse it by running: sudo apt-get install python3

Of course this is a terminal command and since you said Terminal isn't working this is a problem. You can use TTY1 to log in and run this command by pressing Ctrl+Alt+F1. To return to the normal desktop press Ctrl+Alt+F7.