When I enter
sudo apt-get upgrade command in terminal, it finds some files to upgrade but not the Ubuntu new release. Any ideas?
Since 12.04 is a LTS release (Long Term Support), you will first need to go to the window Software Sources and in the last option of the third tab (Updates) state that you are interested in being informed of every new release of Ubuntu (first option in the drop-down list). You will need to enter your code.
Now you can close the window, open the software updater and it will tell you that Ubuntu 12.10 is available.
You can get more information with the
To upgrade to a new distribution, you run