How do I get to the login screen in Ubuntu?
If you do get to a prompt (try 'ctrl+alt+F1' or 'ctrl+alt+F2', the GUI is usually on ctrl+alt+F7) you could try and start the login screen with sudo service lightdm start . If this does work you may have a different problem, maybe installing the display manager again will fix any errors.
What is Ubuntu used for?
Ubuntu comes with everything you need to run your organisation, school, home or enterprise. All the essential applications, like an office suite, browsers, email and media apps come pre-installed and thousands more games and applications are available in the Ubuntu Software Centre.
Are Ubuntu servers free?
Yes. Like the desktop version, Ubuntu Server is free to download and use. However, if you're using it for business-related purposes and can't afford for issues to affect the running, support packages are available from developers. If you prefer to manage the support of the server in-house, that is also an option.