Computer viruses are code written to steal and destroy. They keep systems from functioning normally and they replicate relentlessly. Once inside your computers and devices, they can control programs, corrupt files and even permanently shut down your hardware. Once upon a time, the hackers who wrote viruses were amateurs playing pranks, just to prove their abilities. Today, malware coders are often organized criminals, sometimes even working directly for a foreign government or intelligence agency. The stakes are high, so it’s important to be on your guard and secure your network.