Refers to software that is installed in your computer that you generally do not want and are not even aware of. There are many different types. Parasites can report your Web browsing habits to a marketing company over the Internet (spyware) or change your browser settings to point to a specific site. They can redirect searches to popular search engines to a site that sells a related product. They can cause you to dial up premium services.

Read the Small Print
Parasites are often installed with demos and freeware on the Web. Read the small print. Sometimes you can opt out of that extra utility that will be installed along with what you did want. Be sure your security settings are set to medium at least, and never click "Yes" to any dialog that asks "do you want to run" or "execute" something, unless you know what that something is! ActiveX controls on the Web can not only install parasites, but viruses as well.

Parasites often leave out an uninstall function and are not easily removed, although anti-parasite programs (spyware blockers) can detect and remove them. In addition, various Web sites have parasite detection scripts that analyze your computer and provide you with removal instructions (for example, visit www.doxdesk.com/parasite). See spyware.