I am always asked “how can I get infected?” or “why am I getting infected when I bought antivirus?” I usually pause and smile before I answer. It’s not enough to just have a program for virus. You still have to watch what you are doing and always this thing called the layered approached. You have to be mindful when opening your email, you always have to ensure not only your operating system is updated, but all the 3rd party programs are updated as well. This keeps software patched from many outdated programs from being exploited and leaving you vulnerable. Your habits when you browse is just as bad, which in most cases you can’t always know what sites are bad or have been exploited but having your computer layered with the best protection can help.
Nothing is 100%. You will never be 100% secured. But you can be 98% protected and watch what you do and ensure you adopt habits that will check to ensure everything is up to date.
The best thing to do is if you can’t do it yourself find someone who can, think of your computer as a child or baby, they must get checked up or they will get sick. You must take your PC in to get checked and/or keep them from things that will make them sick.