What are Viruses and Worms?
Simply put, Viruses and Worms are malicious software. There is some overlap between the two, but in general, the difference is how one infects your computer. A Virus spreads by infected files and proceeds to infect other files on your system. A Worm exploits security holes in an existing computer, then hijacks that computers internet connection and begins to attack other computers.

Most Viruses and Worms are designed to attack the Microsoft Windows Operating System, as it is widely used and full of security holes to exploit. However, there still exist Macintosh Viruses and there is even a recorded instance of a Linux Virus, but it didn't get very far.

Virus Scanning
The first, and perhaps most obvious, is to have an up to date Virus Scanner installed on your computer. This is the most basic level of protection and absolutely required for anyone Windows-based computer. The most popular are McAfee, Norton, and F-Secure. None of them are particularly superior to the others, all provide excellent protection. Make certain you connect to the internet on a regular basis and keep your copy updated with the latest virus scanning data.

Personal Firewall Software
A Firewall is a special piece of software that sits between your computer's main software and the internet. Essentially, it acts as a gatekeeper, keeping malicious content out and lets good content in. Even more, it keeps an eye on what your machine is letting out, and can even let you know that you've been infected (by alerting you to unknown content being broadcast from your computer.

Just as a virus scanner is imperative for protecting yourself form viruses, firewall software protects you from internet worms. Worms are malicious software that try to break into other computers on the internet. Windows Desktop machines are a prime target. Whereas a virus will infect files on your system, a worm exploits security holes in your computer's operating system to get in, often undetected by virus scanners.

There are several competing Personal Firewall products, some are bundled with Virus Scanners, others, like ZoneLabs, are stand-alone products. For those who do not have a personal firewall bundled with their virus scanner, we recommend ZoneAlarm Basic, which is free for home use.

Common Sense
By far, one of the most powerful tools against malicious software is common sense. The most common viruses and worms travel through e-mail attachments. Anytime you get an e-mail with an attachment, don't click on it unless you are 100% sure you know where it's coming from and expected it. Don't trust the "From:" address to base this decision off of, it can be forged or your friend or colleague may be infected! If you get a suspicious attachment, e-mail your friend back and ask about it. It never hurts to fire off a quick e-mail asking "Did you just send me X?" and it could save you an awful lot of work trying to disinfect your system later on.

Keep Your Systems Up To Date
Lastly, it's important to keep your system updated. Under the start menu on windows systems is a "Windows Update" program. You should run this often to keep your system updated with the latest security patches and updates from Micorosft. We recommend you run it weekly, lately it seems that's how often Microsoft has been releasing security updates.