I used Norton for 3 years.It is a resource hog.I hated it.
My son put Avast on my computer 3 years ago and I will never have anything else. It's free and it has caught every virus that has tried to get me.It sounds like a siren when it detects something.You don't have to do a thing,it takes care of it right then.
I love it.It updates itself automaticallyand scans your computer constantly.