When “Pop-Ups” pop up
You should never click anywhere in a pop-up window. Even buttons labeled "Cancel" or "Close" or a red-X button in the upper-right corner are dangerous to click; doing so could trigger an infection--the opposite of what you'd expect. To safely close a pop-up window, locate the little x at the top of the window or tab and click or tap on THAT to close the pop-up. 
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