I've attached some Screenshot 1 and Screenshot 2 here.
It shows the window as soon as I boot up. There also appears a (-) red minus sign which tells me that a problem occured while checking updates, and when I click "Show updates" it tells me that the Software Updater has crashed unexpectedly.
I am unable to update it (I wish to upgrade to 16.04 LTS), nor solve the problem. Any solutions?