Thesis 1: Feasible but Not Possible

Remember our discussion on my thesis class. Our prof ask the class to think something that feasible but not possible. And one of the group suggest a topic, a antivirus that no need to update. Of course I disagreed i know that you can create a antivirus that no need to update, and that's for me is possible. But suddenly in the end of discussion me myself and I lose. Our prof says that now a days there's no such thing like that and it is not possible. Do you think it is NOT POSSIBLE? Please let me know your opinion.