I have a system with a dual-boot of Windows 8.1 32-bit and Ubuntu 14.04 64-bit. Ubuntu usually works but after I became root with the command "sudo su" and rebooted my PC it had a Black screen after the Ubuntu logo with the dots goes off. I started Ubuntu's terminal so I can use it to start up Ubuntu but it don't know how. My graphics card is ATI Radeon 3100 Graphics. How do I start Ubuntu with terminal?

1 Answer 1


There are two ways to start your xsession from a text console like tty1 tty2 etc. I can only assume that is what you are referring to when you say terminal. If not, press CTRL + ALT + F2 and then sign in with your username and password.

Once you are signed in, type the following command:

sudo service lightdm start


sudo service lightdm restart

If you are using gnome you may need to use gdm instead of lightdm like this:

sudo service gdm start

Alternatively, you can start the xsession without a display manager. You can use this command to start the xsession and default desktop:


Please post any errors to receive further assistance.

I really don't see how sudo su would cause the problem you are experiencing unless it has to do with one of the commands you entered after becoming root.

  • how do I tell if i'm using gnome? Aug 2, 2014 at 4:33
  • 1
    @kprovost7314 the lightdm command will output something like "lightdm: unrecognized service"
    – mchid
    Aug 2, 2014 at 4:38

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