Norton™ AntiVirus 12 for Mac® won't launch

Hi, I just bought Norton™ AntiVirus 12 for Mac® but although I've installed it, it won't run. When I double click the download, a pop up appears with the Norton AntiVirus Guide and Norton AntiVirus Read Me icons, but the image for the Norton AntiVirus Installer is missing. And when I double click the latter, another pop up window appears saying the following: "“Norton AntiVirus Installer” is an application which was downloaded from the Internet. Are you sure you want to open it?" I click accept, and then nothing happens. Could someone please help me? Thanks

The read me is a text file and the user guide is a pdf file. If you double click on them it will open the TextEdit or Preview app respectively.

 

If the installer app is missing, it shouldn't give you the dialog of the app being downlaoded from the Internet. Could you post a screenshot of what happens when you click on the Norton Antivirus download?

 

Thanks!