Ubuntu 14.04 upgrade is hanging

[ana17]

I installed Ubuntu yesterday. Today when the system prompted me to update to version 14.04, I agreed to it.
Now, I have the Distribution Update window open, but it is hanging while "preparing libc6"
The system monitor won't open, neither will the command line.
How can I exit the update or make it continue it so that my computer stays safe?

[Impavidus]

You installed Ubuntu yesterday (which version?), and today you try to upgrade to 14.04? Why didn't you install 14.04 in the first place? Or 16.04?

As this is a fresh install and you haven't really done anything, I suggest a fresh install of the latest version. 16.04 has 5 years of support and, although not as solid and bug-free as 14.04 yet, is a very good system.