Overview of Viruses, Worms, Spyware & Trojans

All confusing terms! Here is a brief overview of what each of these
terms mean:

Viruses can attack your computer from many sources including email attachments, so it is very important you don't open emails from unknown sources. It's especially important you don't open email attachments which you are not expecting or which come from sources you do not trust.

Worms are destructive programs that replicate themselves throughout your computer, sometimes by exploiting security vulnerabilities in the operating system.

Spyware is software which can be automatically loaded onto your computer without you knowing, when you visit websites or install new applications that may secretly contain it. It collects your personal information and can secretly send this information to a third party.

A Trojan is software that at first glance will appear to be harmless software but will actually do damage once installed or run on your computer. Trojans can introduce viruses and leave your computer vulnerable to attacks by hackers and intruders.