There are many security software programs on the market today providing various levels of antivirus protection. They usually contain additional tools and components, such as antispyware, file protection, a real-time shield, etc. It can be difficult to choose the best application for your needs as each one has its own strengths and price points, although free versions are also available. The most popular antivirus software available on the market are Kaspersky, Norton, Avira, Bitdefender etc.
Personally, I've used all of them and they are doing great job but from my experience the best antivirus by far is F-Prot. I highly recommend it. You can try it here