Well as I said, stay away from dodgy sites and you'll be fine. I've been using a Windows laptop for 8 years (my sister's) without any Antivirus solution and we haven't had more than 3 virus attacks and that was only from opening suspicious keys.well i dnt trust windows defender looking at all the loopholes that were present in internet explorers, I think that's the same case with windows defender, and i feel more secure using a product from a core cyber security firm rather than some other company which only made theAV security software as their holiday project......
Windows Defender is more than sufficient for the everyday user, not for people who torrents and does prawn.