Internet security is a complex subject, too complex for a brief article like this. So here I'm sticking to a few of the most important basics. If like so many Internet users, you are clueless about what is the best Internet security and how to get it, hopefully this article will help.
First on your list of defenses should be a good firewall. Your firewall will prevent unauthorized access to your computer from any external source, and the settings can be varied from low security to high. Another thing the firewall does is generate a log file capturing connection details, such as those of the systems which are trying to gain access to your computer, as well as record the data that is being sent out by you. Windows XP / Visa provides a firewall by default. Alternately, you can download a number of very good free firewalls like Comodo and ZoneAlarm.
Next, you need a good antivirus program. A virus is nothing but a malicious computer program written to muck up the workings of your computer by corrupting your hard disc and data files. Viruses come in many guises. One of the most common is the Trojan horse. Like its Homeric predecessor, Trojan horses are seemingly-benign invaders – they enter your system disguised as something other than what they are and then destroy or steal your personal information without your being aware of what's happening. Then there are the worms. Worms are malicious programs which replicate themselves and spread to your entire computer network, often resulting in its total breakdown.
One of the best Internet security precautions you can take against viruses is to swear an oat to never open an email attachment unless you're positive it's safe (eg, from someone you trust). Beyond that, you need antivirus software. Some cost money, such as those supplied by Norton and McAfee. Others are free, like some of the programs offered for free download by Avast and AVG.
Anti-Adware and Anti-Spyware
Adware is software that causes those annoying and distracting pop-ups. Spyware is a little different. It grabs info off your computer and passes it onto its remote master. Both adware and spyware can ride piggyback on the free software you download, then latch onto your system files and corrupt them. These types of "malware" are nearly asothersome as a virus, though they seldom do direct harm to your system. Your best defense against adware is anti-adware, such as AdAware. But more importantly is protecting your system against spyware, and to accomplish this, try ZoneAlarm Spyware. Needless to say, Norton and McCafee also supply anti-spyware.
Secure Web Browsing
For a more secure web browsing experience, it's a good idea to disable third party cookies that let the advertisers keep track of your system (in IE, click on Tools, then Internet Options, then Privacy).
Another simple yet effective methodology is to enable "warning text boxes" that will alert you if you are entering an unsecured connection (in IE, click on Tools, then Internet Options, then Security, then Custom Level). A couple useful add-ons to keep in mind are Ad- block, which prompts pop-ups, and no script, which protects you from XSS attacks by allowing scripts to run only from the sites that are trusted by you.
The IE 1.7 browser comes with an extended validation certificate (EVC) that allows you to see SSL certificates of companies you are thinking of doing business with. This serves to enhance e-commerce security as a Web vendor has to undergo a certain amount of vetting to obtain their SSL certificate. This extension validation of the vendor website at least provides some assurance that you are interacting with an authentic website and not a malware or a phishing website with fraudulent encrypted certificates. Incidentally, Firefox 3 and Google Chrome also come with EV certificates. So for safer browsing and assurance of best Internet security always shop using an EVC browser.