Computer viruses have been a source of trouble for individuals and businesses for decades. Their malicious strength ranges from mildly annoying to incredibly destructive. In some cases, they can wipe out entire computer systems, or even whole networks if durable enough. To know how to properly combat these vicious foes, you must understand how a virus functions and some of its basic properties and characteristics.

Viruses are computer programs, designed by an individual or team to infect a device without the user becoming aware of the breach. The main purpose of a virus is to corrupt the files of a computer and ultimately render the system useless. Many viruses are launched by hackers simply for their own personal entertainment; in fact, some of the most malicious viruses in history have this root. Sometimes, the goal is more productive, such as wanting to destroy a competitor's computer network to make one's own business stronger.

People often get confused as to the differences between viruses, worms, adware, malware, and Trojan horses. The defining characteristic of a virus is that it needs to attach itself to a program, or host, in order to replicate and spread. Worms, on the other hand, can survive on their own without a host. Adware does not exactly have a malicious intent, although few computer users want it on their systems, as the software displays advertising even when the user is not on any web pages.

Trojan horses appear to be harmless files, but actually open the door to hackers to further devastate or commandeer a node. Malware is an umbrella term which covers everything previously mentioned, plus unique software which does not fit the characteristics of other programs but is still malicious.

The best way to avoid viruses is to not receive them in the first place. You can steer clear of the majority of viruses by simply being careful. Being careful includes not opening spam emails, not downloading programs you are not familiar with, and putting strong passwords on to all of your computer accounts. If you take a strong amount of caution in all of your computing activities, there is a good chance you will not ever have to deal with a virus-related problem.

However, sometimes infections are unavoidable. Viruses travel from file to file, corrupting each one, and they travel from computer to computer when one of those corrupted files is sent out. A friend or coworker could unknowingly send out a corrupted file, thus infecting every recipient.

Businesses have become aware of the consumer and industrial need for virus protection. Several companies, such as McAfee and Avast, sell anti-virus software which automatically scans for viruses, worms, and every other type of malware. Whenever the program finds something particularly strong, it notifies the user and offers them several options, such as deleting or quarantining the threat. Garden variety viruses are rooted out in daily scans, and although these kinds of viruses may not be serious, they do inhibit the operational speed of any computer.

Anti-virus programs must be updated on a regular basis, so the software's registry can be filled with new virus signatures, which are unique strings of bits inherent to different viruses. Certain viruses are labeled as metamorphic, in that they change each time they are copied, making them hard to track. As long as your anti-virus software is kept up to date, you should be able to contend with anything that is thrown at you.