Viruses, Worms and Trojan Horses are all malicious programs that can cause damage to your computer, but there are distinct differences among the three.
Knowing the differences can help you protect your computer from their often annoying, and sometimes damaging effects.
The most common reaction people have when the topic of computer "malware" arises is to refer to all forms of them as viruses.
While the words Trojan, Worm and Virus are often used interchangeably, they are not exactly the same.
Computer viruses are written specifically to change the way a machine works, without the knowledge (or permission) of the user.
They behave in a similar way to biological viruses, replicating themselves as they go, and passing from computer to computer.
Like a biological virus, a computer virus can range in severity; some cause only mildly annoying symptoms while others damage your hardware, software or files.
A virus cannot be spread without human action, (such as running an infected program) to keep it going.
People continue the spread of a computer virus, mostly unknowingly, by sharing infected files or sending e-mails with viruses as attachments in the e-mail.
Computer worms are similar to viruses but can spread from computer to computer without any human action.
They're written to take advantage of vulnerabilities in operating systems and software.
The real danger with a worm is its capability to replicate itself on your system, so rather than your computer sending out a single worm, it could send out hundreds or thousands of copies of itself, creating a huge devastating effect.
One example would be for a worm to send a copy of itself to everyone in your e-mail address book (this is a common trend that most of us have encountered).
Due to the nature of a worm and its ability to travel across computer networks the end result in most cases is that the worm consumes too much system memory or bandwidth, causing computers to stop responding.
A Trojan horse is loaded with as much trickery as the mythological icon it was named after.
It will likely appear to be useful software but will actually do damage once installed or run on your computer.
Those receiving a Trojan horse are usually tricked into opening them because they appear to be legitimate software from a legitimate source.
Some Trojan horses are designed to be more annoying than malicious, like changing your desktop or adding goofy icons, or they can cause serious damage by deleting files and destroying information on your computer.
Trojans are known to create a "backdoor" on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be stolen.
Combating Viruses, Worms and Trojan Horses The first step in protecting your computer from any malware is to ensure that your operating system (OS) is up-to-date.
This is essential if you are running a Microsoft Windows PC.
Secondly, you need to have anti-virus software installed on your system and ensure you update it frequently.
Additionally, you want to make sure your anti-virus program can scan e-mail and files as they are downloaded from the Internet.
If you suspect that your PC is infected with any of these malicious bugs there are plenty of qualified experts that can assist you.
You go to great lengths to protect your personal belongings, don't forget about your personal information.