internet wont work at all

[Moths_]

I just installed linux mint 20.2 cinnamon
this is my first time ever touching linux

the internet refuses to connect even though it recognises it existing (using ethernet)
i cant update anything it says "failed to fetch" and then a http link when I do 'sugo apt-get update' and when I try to update from the menu thing
firefox says no connection to server, and ive tried the enable network option in the recovery mode.
im using a thinkpad T440, if thats any help. but yeah i just want to know if i can manually add the missing files and if that will fix it?

forgot to mention in the recovery mode screen theres an option to fix missing packages or something along the lines of that, when i run that it does the failed to fetch thing but when i give it the go ahead to fix it, it fails?? i really dont want to install a different type of linux or whatever so im really hoping ill be able to fix this problem

[Pjotr]

First establish temporary internet connection for your computer by means of your cell phone.

Please generate an overview of your system like this:

- Launch a terminal window (this is how to launch a terminal window);

- Make the terminal window full screen, to avoid chopped lines;

- Copy/paste this command into the terminal:

Code: Select all

inxi -Fxpmrz

(if you type: the letter F is a capital letter, and don't omit the space after inxi!)

Press Enter.

Copy/paste the output in your next message.

Do the same with the following four commands:

Code: Select all

rfkill list all

Code: Select all

iwconfig

Code: Select all

lsusb

Code: Select all

lspci