Antivirus security software
A computer system that has a connection with the Internet or has contact with the rest of the world in some other way needs a virus scanner. The effects of virusses vary from a harmless joke to slowing down your computer, the deleting or corrupting of data, sharing your sensitive data with the rest of the world or granting hackers access to your computer. Virusses spread mostly through e-mails and programs, and every day new ones come out. Most virusses are written for popular operating systems, and older versions of software tend to have security problems, so make sure you always have a working virus scanner with the latest virus definitions installed on your computer and preferably also the latest version of your operating system of choice.