The terminal is gnome-terminal. xterm might not be available if you don't install it with "apt install xterm".

Can't you start the terminal from the icon in the dash?

I tried with the icon in the dash, I tried also through Show all aplications. Both of them are not working.
I have to do ALT+F2 to execute xterm, and a new terminal is open. I did´t "apt install xterm" because I can not open the Terminal or Root Terminal.

Are there errors related to this in the journal?

Have a look with "journalctl -r"

Do this in a text console (CTRL+ALT+F1) if you are not able to start a graphical shell...

Do you have enough memory in your machine (cf free)?

Please try to do some basic investigation as you're not providing any data.

If the gnome terminal is not working, you can install "xterm" and try to run this one (possibly via ALT+F2 if there is no icon for it)... and then run "gnome-terminal" on the command line to see if there are errors.

ou yeah... is in the journal...
Journal show me a lot of things, I think in this line explain everything.

Maybe in this line advice me about the error:

gnome-termina.desktop[1572]: Error constructing proxy for org.gnome.Terminal:/org/gnome/Terminal/Factory0: Error calling StartServiceByName for org.gnome.Terminal: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ChildExited: Process org.gnomeTerminal exited with status 8

I tried to start "gnome-terminal" from ALT+F2, but nothing...

The PC is a new Desktop, AMD FX8320E, 16Gb ram, AsRock 970 pro3 r2, 1Tb HDD, 2x HD5970. I don´t think the problem is for the hardware but in this point I don´t have idea...

Thanks you very much for your time and your faster answer.

So this seems to be a FAQ:
https://wiki.gnome.org/Apps/Terminal/FAQ#Exit_status_8

Please reset your locale to a UTF-8 locale (dpkg-reconfigure locales), reboot and see if the problem persists.

What locale were you using? ("locale" command should output the information)

I can not select the language in the installation, just go directly to "keyboard language".

After run "locale" I have all the locale in C, except: "Language" and "LC_ALL=" are empty

After "dpkg-reconfigure locales" I select "es" (Spain) and then "C.UTF8"

I reboot and.... SOLVED. IS WORKING!!!

I don´t know why in the 6 installations I did, I can not select the language and skip this step. But now I know how fix it, I hope that can help also another people.

Thank you very much for your time. Have a very nice weekend!!

Thanks, closing the ticket.