I recently did a clean install of Ubuntu 18.04. I did this because I was having trouble with my computer not booting on 16.04. At first when I upgraded everything worked fine and booted normally. But recently I haven't been able to login, when I enter my password/ username is just goes in a loop and asks me for the password again. I am using a Dell XPS 13 and doing CTRL+ALT+F1 or any other function key during the login screen doesn't work. So if someone could provide some insight into this, that would be great :).