I encountered thesame problem after upgrading to 12.04.

The followingsolution worked for me:

1.            Open this file in a text editor as root:

2.                  gksu gedit /etc/network/interfaces

3.            Add these lines to the file:

4.                  auto eth0

5.                  iface eth0 inet dhcp

6.            Save the file and quit the text editor.

7.            Now restart the network:

·                       How to restart thenetworking service?

 Ovde mi NE da da snimim fajl, pise read only, valjda jer nisam pokrenuo gedit kao root, sigurno jer nije instaliran nego testiram ubuntu.

Try this...

Press Ctrl+Alt+T and type echo on |sudo tee /sys/class/net/eth0/device/power/control

After that, logoutyour machine, pull out the ethernet cable and then plug it in again afterlogging it in

Ovde kaze permission denied.

Imam 2 particije po 50tak gb na kojih imam 7 i 8, i jednu od 900gb gde su mi bitni podatci.

Koliko particije trazi ubuntu i kakva treba biti? Strah me da ne zaje**m nesto pa da odu svi podatci u p.m.