How to shut down my computer?

I can't find a dialogue anywhere on the desktop (like on Windows Start/shutdown) to shut down Ubuntu. I downloaded and ran the Ubuntu live CD and after I ran it, I couldn't shut it down. I had to hold the on/off key on my computer for 4 seconds to shut down my computer to get back into Windows. If there is a button somewhere, why is it not obvious?

Solution 1:

Go to the upper right corner and use the gear menu to select Shut Down.

Solution 2:

You can also momentarily press the power button, and a pop up dialog will appear with buttons for suspend, hibernate, restart and shutdown.