Security Popups

This may not be the right place for this but here goes. I keep getting a popup at the bottom of the screen that reads "Only secure content is displayed. Do you want to display all content?" Then a pop up in the middle of the screen tells me about the sites certificates etc. Asks do you wish to continue? I do not know what is causing these so called security alerts or where they come from. My antivirus is Comodo if that helps. Thanks in advance for any help or suggestions.

 

What Operating System and Browser type are you using?

This often happens when you access online stores or financial websites, that display images, banners, or scripts that are coming from a server that is not secured.