I have a desktop with NO internet but it did before, I am trying to play my games but, when i go to play 30 minutes later a blue screen comes up and shuts down my computer saying it is under risk or something.. I am thinking it needs a BETTER virus protection because of what had maybe been installed on it before.. What is the best virus protection to use for windows that is FREE!?? Also, How can I download it from my mac onto my USB drive and then onto my windows?? All answers are appreciated!