This is a free non-commercial version which can be set to update automatically. However to get complete coverage you will need to upgrade to the paid for version. This means that if you run the free one you will have to run Malwarebytes and Stinger etc occasionally if you are to be safe.
An excellent free Virus checker to check a computer suspected to have a virus. On this link you will not only find the downland button but instructions on how to use Stinger.