The Internet is a virtual dark alley. Unscrupulous dealers lurk in the shadows; you’re never sure who you can trust. In this cyber-city, potential infections lay in wait under each hot link and e-mail attachment, ready to corrupt your system with malware.

Malware is the all-inclusive term for malicious software that is in abundance on the Internet.

The computer virus, perhaps the most infamous, is a program that spreads within a computer or from one computer to another without the users’ knowledge or consent. Damage from a virus can be as little as a pop-up or as destructive as wiping your hard drive. It can degrade your system by corrupting it and robbing it of its resources.

Not only can a virus change or delete data, it can bring your computer to a crawl by using memory, disk space and bandwidth.

Many viruses come disguised as other programs and will try to trick you into either replicating it or initiating the spread of personal information.

In the case of the current XP 2008 Virus, a pop-up warns of infected programs and eminent danger. It appears to originate from Windows, with the same format and color schemes as the operating system.

The only thing though is that Windows doesn’t warn of viruses. That is not its job. Your antivirus program would do that. But the program preys on your fears, hoping you would click on it to "fix" what supposedly ails it. In reality, you would be spreading the virus with a click of the mouse. The best thing you could do is to get, keep updated and use a good antivirus utility.

A bot is a specific type of virus that runs automated tasks across the Internet. It mostly initiates click-fraud, harvesting personal information as user names and passwords. A worm is specific form of virus that runs itself. It doesn’t need a host to cling to in order to replicate itself across the Internet.

Spyware is a program you get unknowingly by installing certain shareware applications. A free download is tempting, but everything has its cost. Even though you may not have to pay for that program, its author is paid by a marketing company to include code in it to spy on you. Big brother is watching.

What it can do is track your browsing habits and report back to the mother ship. Spyware collects data with the purpose of informing advertisers what you’re likely to purchase. Ever wonder why, for example, after you browse some car sites, you start getting spam from auto companies or car dealers?

Adware is software sponsored by advertisements. These free programs have ads within them, either promoting a higher-end product for sale or others of that company’s products. Sometimes it will even take you to their web site. Others may hijack your homepage, replacing it with their own. All of this will slow down your system, again due it being robbed of its resources.

A Trojan horse is an Internet version of the same old thing. In this case, don’t trust spammers bearing gifts. The Trojan is a program masquerading as another, clandestinely hiding in its host until it’s ready to strike.

Phishing is not done from a pier, but there is bait involved. You are being baited by a bogus e-mail into thinking it is something it is not.

The phishing scam will have a link in a disguised e-mail asking you to provide personal information. It appears legitimate, as if from your bank, eBay or a company you may have done business with. It will ask you to click on a link and update your information, usually including your user name, password and credit card information. The link will take you to the scammer’s site, not your bank’s.

The best way to spot these frauds is by the generic greeting. They will say, "Dear customer, " or "Greetings." Your bank will not only not contact you by e-mail for something like this; they will call you by your name. The phishers will not. So don’t get caught.

Cookies can be good or bad. Some programs use them to track you, others to identify you. When you join a Web site and need to log in with a user name and password, a cookie is formed. This way when you return to that site, you’re greeted with, "Welcome back, Bob," because it knows who you are. It saves you the trouble of logging in each time.

But if you want to delete the tracking cookies, get a program like the free Ccleaner (www.ccleaner.com) that allows you to pick and choose which cookies to keep. Really, the best defense is to judiciously choose which e-mails to open and what sites to visit.

That said, I agree with Murphy: What can go wrong, will. Back up everything. Viruses happen.