Why would you blame a security software for your ignorance? No offense, but what you describe seems to be ransomware, and if so was the case, ransomware sucks but it is easy to spot. Due to Flash vulnerabilities, sometimes you're not even needed to download infected software. And new ransomware is delivered everyday, and known ransomware are updated every hour. So don't expect a 100% efficient anti ransomware protection, when you know we're talking about sig-based security suites and not sig-less software. If you really are so paranoid about not being protected, purchase a next-gen antivirus software with it's sig-less based databases and forget about this.