I think I may be running two instances of Ubuntu at the same time

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http://askubuntu.com – When I log in, usually I see my background and a box with my username and asking for a password. However, recently, I see my desktop (complete with the task bar on the side and top and battery indicator and I can shut down or restart and everything) and when I log in, everything seems to be normal but then I realized that behind the icons on the left side there is actually a 2nd set. Everything works normally, I'm just scared because this has never happened before. And I have tried shutting down and restarting. In the screenshot you can see that behind the icons there is a 2nd, different (HowTos)