If your browser is constantly being redirected to Greatzip.com or you are seeing popups promoting GreatZip then you are most likely infected with some sort of adware infection. Adware is a type of computer program that displays advertisements in your browsers or directly from your Windows desktop. These advertisements can be very intrusive or appear whenever you click on a link on a web site.
This article was published first at How to Remove Greatzip.com Popup Ads and Advertisements
Source: Bleeping Virus