Is there any other way to access a terminal from the usual desktop.
Yes. If your system is "really, badly broken" you can usually login to a text only terminal with
<CTRL><ALT><F2> from the GUI.
Or boot to "Rescue Mode" from the grub prompt.
You get a boring, but ultimately useful, login screen.
Login as yourself, explore, and fix things up if you know how to.
<CTRL><ALT><F7> will send you back to your GUI. It ("X") may have to be restarted ( with <CTRL><BACKSPACE> usually ) for the changes you have made to be recognised.
BUT: once you have installed any linux distro, the first thing you should do is apply the updates (because your installation media will be out of date already.)
Login however you can to your 'buntu and then try this
# Refresh the repository list
sudo apt-get update
# Now install the newer versions
sudo apt-get upgrade
Sit back while it does its thing.
Answer "Yes" if you are happy when you have read the text (if any).
Any better ?
This same condition also pops up when I need to enter a password.
Passwords are often not echoed to your terminal. This is normal linux "security" behaviour (who is looking over your shoulder?). Just type it in and press RETURN. If it fails, you got it wrong, pay more attention and type it again, s l o w l y if necessary.