The terms "spyware" and "adware" are often used interchangeably, but there is actually a large difference in what these two different types of malicious software can do to your PC and how you should detect and remove them. While some pieces of sofware can technically be called spyware and adware, most malicious software programs fall into one category or the other.

The term "malware" has been coined by computer experts to describe any piece of software that is installed on a computer without the owner's knowledge with the express purpose of doing something harmful, illegal or secretive. The word malware is actually short for the phrase "malicious software" and pretty much describes exactly what you're getting when your computer has become infected with spyware or adware.

Spyware programs, as the name implies, is often installed with the express purpose of somehow spying on your computer activities. Spyware can sometimes track and log what you type on your keyboard and then send those strokes back to someone else who wishes to do you harm. This type of spyware is called a keystroke logger and it can be very harmlful. With a keystroke logger someone can get all the usernames and passwords you've typed into your computer, can possibly read all the email you've written from your PC and even obtain your credit card number if you've ever typed it in to purchase something online.

There are many different types of spyware and not all spyware programs do the same thing. Some spyware programs simply monitor your online activities, which violates personal privacy but may not actually break any real laws. Other types of spyware can secretly spread computer viruses or do damage to your computer. Yet other types of spyware can simply change the settings on programs that you've legitimately installed. If you've ever had your web browser's home page change without your knowledge then your computer may be infected with spyware.

Another type of malware is called adware, and it's designed to do just the opposite of spyware.

Adware, as the name impllies, is designed to bombard you with annoying pop up ads or other types of advertisement, in the hope that you'll buy something or accidentally click on an advertisement that makes the installer some money. Some adware packages only work when you're connected to the internet, while other adware programs function all the time.

In recent years adware programs have gotten sneaky. Many adware programs now make their pop-up ads look like fake Windows error messages, causing you to click on them by accident. If you've ever gotten strange Windows error messages and you weren't sure what to do then you may have some form of adware installed on your PC.

You may have adware or spyware installed on your PC and not even know it. If your PC is slower than it once was, if you've noticed the hard drive running at strange times or if your web browser's home page has ever changed without your approval then you probably have spyware of some sort installed on your PC. Adware is more obvious: if you're getting a bunch of ads or suspicious error messages that you didn't get before then you may have adware installed.

Fortunately there are many good and affordable spyware and adware removal programs available. Some programs specialize in one type of malware over the other, so it's a good idea to have some general idea of the category of malware you think you have. You simply need to install and run them and your PC can be spyware and adware free in a matter of minutes.