The Internet and the World Wide Web are full of interesting places to visit and sources of information. They are also full of risk. Malicious computer code embedded in innocent-looking files and Web pages, can damage your operating system or software, steal data from your computer or turn it into a conduit for junk e-mail without your ever knowing anything has happened. This sounds pretty scary, but the risk is manageable if you understand the nature of the risk, how to avoid becoming some hacker’s victim, and a few things about preventing infections and intrusions and how to clean up if your computer is attacked.

All computer users can learn and should know how to provide basic security for their systems and their home networks so they can minimize their down-time and avoid repair bills.  That’s the purpose of this series of articles. To begin here is a list of some of the terms you will come across most often when the subject is personal computer security.

Malware – A computing neologism made up of the Latin-derived "mal," meaning "bad" and "ware" from "software. Malware is a generic term for destructive or disruptive computer programs and files.

Virus – Malware that is embedded in some other program or file and spreads by exchanging copies of the original infected file or files generated by infected software.

Macro-virus – A macro is user-generated code that modifies some action of a word processor or spreadsheet program. A virus can be written using the native macro language of one of these programs. The macro-virus will infect all documents generated by the compromised program. Anyone else receiving a document from the infected computer is also at risk of infection. Microsoft Office was the target of choice for macro-virus writers in the 1990's, but no new major macro-virus threat has been identified for several years.

Trojan – Malware that has no built-in means of transport. Users are typically tricked into loading the code because the file is made to look like something desirable ("cool screensaver"…"password file to 10,000 porn sites"…"nude pictures of Britney Spears"). However, when the user opens the file, instead of revealing the promised pictures of an undraped teeny-pop diva, the file releases a malicious program on the unlucky person's computer.
 
Worm – Malware that can provide its own means to "travel" across the 'Net. The most common mode of transport for worms at present is e-mail. The program code for a worm can include an e-mail function that allows it to mail copies of itself from one computer to another.

Spam – The common term for "junk e-mail." Depending on whose figures you trust, 80% or more of the e-mail traversing the 'Net is spam.

Spyware – Spyware can take many forms, but what it does is gather information about your computing habits and make that information available to someone else without your knowledge or permission.
 
Adware – Adware can be legitimate software that users knowingly load on their PCs. Many of the free widgets available on the web display ads in their interfaces. Done fairly and honestly, selling advertising space puts a dollar in the pocket of the software developer and gets you a free tool or toy. However, some adware runs covert data collection processes (see Spyware).  

Denial of Service Attack (DOS) – This is an assault on an Internet host intended to make it unavailable to 'Net users. DOS attacks can be technically complex and require breaking in to a server or router and damaging or modifying some part of its operating system or they can be simple attacks involving flooding the victim network with data or access requests from multiple computers. If the attack is launched from a number of compromised computers, it's called a Distributed Denial of Service (DDOS).

Anti-virus – Software designed to detect, identify, deactivate and remove viruses and other forms of malware.

Spyware scanner – Software designed to detect, identify, deactivate and remove spyware programs and files.

Firewall – Software or hardware device to control entry to and exit from a single computer or a computer network.

Process List – A program available in modern operating systems that shows what programs are running and allows the user some control over running processes.

Knowledgebase – An information database compiled by a manufacturer or technical support group. You can consult a knowledgebase for information on specific technical problems.

Search Engine – Google, Yahoo and others  are excellent ways to find information on computer problems.

Common Sense – This is probably the best tool you have for keeping your computer safe. Make good use of it.