When you talk about a "computer virus," odds are that what you actually are talking about is what security professionals call "malware."
"Malware" is a broad term that covers a host of malicious software. At its simplest, malware is software that’s been designed to do bad things. Whether it’s a keystroke logger recording your personal information or a computer worm infecting systems, or even adware you didn’t consent to they all have two things in common: they’re all software and they’re all doing bad things.
People often use the term "virus" to mean "malware" because viruses were really the first kind of malware. In fact, these days, viruses are one of the less common forms of malware that you’ll encounter. Worms, adware, spyware, bots are all more common than the classic virus.
Where it is important to understand the distinction between viruses and malware is when you’re looking at security software. Generally security companies will call their products "antivirus" when referring to products that protect only against viruses and worms. These products will typically not protect against adware, spyware, phishing and other types of malware. If you want protection against these other kinds of threats, you want to be looking for specific anti-malware capabilities in the product description.
Whether you call them viruses or malware, though, the fact remains that we’re talking about bad software. And it’s bad software that can lead to things like identity theft of financial fraud and loss for you or your family, or making your system a zombie computer that’s part of a botnet, or even a denial of service attack that may take down a major website. If you’re the victim of a virus or malware attack, regardless of whatever kind of malware it is, it’s going to be bad news for you. The best thing you can do is prevent it from happening in the first place by having a modern security package that provides anti-malware as part of its comprehensive protections.