Since one of our compatriots already shared Lesson 1 of my Computer Security 101 series I thought I would officially add the lessons to the Tutorials forum here on AO. However, due to copyright and legal restrictions I can't simply post the whole thing. I am going to post a big chunk of each lesson and then link back to my original article for those who wish to read the entire lesson at About.com.

The first 7 lessons of the Computer Security 101 series discussed various technologies and terminology associated with using computers and being on the Internet and what some of the major pitfalls are. The goal is that hopefully by knowing a DNS from a DHCP from a DoS you can better understand the nature of new threats when you hear about them and what you should do to protect your computer or network.

This lesson will pick up where Lesson 8 left off- talking about the different steps you can take to try and make your Internet experience safer and protect yourself from hackers and malicious code.

Lesson 8 covered vulnerability patching, shutting down your system when not in use and making sure you know what a program is before you execute it.

These probably should have been in Lesson 8, but we’ll start Lesson 9 with two of the most important preventive measures- run a current antivirus software program and a current personal firewall program at all times.

Antivirus software blocks known viruses, worms, Trojans and other malicious code by comparing it with signatures of known malware. Most antivirus software also has the ability to perform heuristic scanning which uses known signs or patterns of malware to try and detect viruses or worms that aren’t yet known and for which your software doesn’t have a signature to match it against.

There are generally three components to antivirus software. One monitors incoming email and email file attachments. One monitors incoming Internet traffic and file downloads. The third one scans your entire computer in the background while you work. If you find a suspicious file you can choose to scan that file manually.

Instead of trying to guess if that message from support@microsoft.com with the MPG file attachment is legitimate or not, your antivirus software should immediately flag any known viruses or other malicious code and alert you. You can usually configure how you want virus detections handled- automatic quarantine of the file, automatic deletion of the file or you can have the antivirus software ask you at each detection how you want to handle it.

If you don’t want to spend money to buy an antivirus program you can check out free antivirus applications at Free Antivirus and Virus Removal Software .

Full article- Computer Security 101: Lesson 9