Licenses found on the Internet never last long, so I switched to Free antiviruses. If you try Avira AntiVir or security software from EmsiSoft, both free versions, you will never need a Paid Antivirus. In my opinion, Avira beat many known paid antiviruses for its detection rate. Besides that, does not exist an antivirus that can protect you 100%. I don't say to buy an antivirus is like throw out the money, but with Avira installed I don't feel the need to change. Enough said, I think.