Most people are familiar with viruses and the need for virus protection software, but when you start talking about spyware, adware, malware, trojans... it all starts to get very confusing.

In short, Malware is any program or file that is harmful to a computer user. But there are various kinds of malware; the most common are spyware and adware. Adware is designed to infiltrate your computer and throw advertisements at you, hoping to get you to purchase something... just like any other ad you would see at a website you're visiting, except that it "came to you" versus just being out on the web somewhere.

Spyware is much more dangerous. Spyware is designed to gather information from your computer and report it back to a host computer somewhere out on the internet. It might be sending back your passwords that you use to log into stuff like shopping sites or your bank, or it may be more direct... searching for files on your computer that contain personal or financial information.

And some malware is even designed to install viruses, and vice versa. There are a mariad of programs available to detect all of this bad stuff. Some is more expensive than others. Some only scan "on-demand" while others scan "all the time" - some work in conjunction with others, while some prefer to work alone.