You only need one anti-virus...having too many causes them to 'run into' each other, thus causing problems with your pc, and possibly major ones in the long run. I would reccomend getting rid of Norton. It basically takes over your pc, and deletes files or programs without asking, especcially on usb's and external HDD's. AVG is much easier, and user friendly, it always double checks with the user before doing things such as deleting stuff. There is a free and paid version, anyone of them does the job