best antivirus for PC

These days my computer does not know how, often a problem, but no way, I took the computer to a computer system, and now finally is good, finally can be in normal use, I go to the computer repair computer repair training yesterday, the teacher introduced me to say there is a best antivirus for PC is very good, and now a lot of people are using best antivirus for PC, very convenient, but also to protect the computer can effectively, so I just last night to play computer to download a best antivirus for PC did not think that now the computer is really use up more smoothly, no card.