I use NIS 2012. I know in my case, as soon as I download a malicious file it quarantines or deletes it immediately before I even touch the file. I also have had cases that during download it will terminate the download stating it contains a malicious file. With the Norton community feature, a good majority of the time it will tell you that a specific site is known for malware or viruses and will block the site from even loading without the user's confirmation that you are sure you want to. And in which case it won't let you download it without user intervention and confirmation that you are sure you want to download the file. Even after that it will delete or quarantine it immediately. And if for some reason you are able to download a malicious file, Norton NIS scans the file when you try to execute it before actual execution and will delete or quarantine it.