Malware is an abbreviated term used to describe a "malicious software" program. Malware includes things like spyware or adware programs, such as tracking cookies, which are used to monitor your surfing habits. It also includes more sinister items, such as keyloggers, Trojan horses, worms, and viruses.

A keylogger is just what it sounds like. It is a program that logs every keystroke you make and then sends that information, including things like passwords, bank account numbers, and credit card numbers, to whomever is spying on you. A Trojan horse may damage your system, and it may also install a "backdoor" through which to send your personal information to another computer. These forms of malware are commonly used for perpetrating identity theft.

A virus or a worm replicates itself and may hijack your system. These types of malware may then be used to send out spam or to accomplish a variety of other unsavory activities, and you may not even know it. Viruses usually attach to other programs, while worms are self-contained. Both can cause severe damage by eating up essential system resources, which may lead to your computer freezing or crashing. Viruses and worms commonly use shared files and items like email address books to spread to other computers.

Any type of code or program that is used for monitoring and collecting your personal information or disrupting or damaging your computer, may be referred to as malware. In fact, malware can be any type of malicious code, even if it has not yet been identified as a worm, Trojan, etc. Good anti-virus programs can be configured to scan email for any type of malicious or suspicious code, and alert you to its presence, even if it is not currently recognized malware.

Anti-virus programs are good protection when kept up to date. However, they frequently miss certain types of malware, such as Trojans and spyware, so it is a good idea to run at least one anti-adware program in conjunction with anti-virus. Running two is even better. Utilizing a firewall is also helpful. While it won't keep malware out, it can keep such programs from accessing the internet and delivering your personal information to the intended target.