Although the cheapest option, do ask yourself if free anti-virus software safe to use at least once a year
Any free anti-virus software can initially be brilliant but not so effective a few years later. The efficiency of anti-virus software programs can vary year on year. So we would recommend that you don’t assume that the free anti-virus software you installed years ago is still the best option. It may well be, but it is worthwhile spending five minutes checking out your options every two or three years.