Don't let your computer get infected by Spyware.
Spyware is one form of malware (a global name for things you don't want to find on your computer). Spyware is usually written for commercial gain. Once it is on your computer you will find that your computer slows down and the internet can become unusable as your web browser is sent to unwanted sites, or unwanted tool bars appear in your browser. Older web browsers might also allow unwanted pop-up ads
How to Prevent Spyware
Make sure you are using the latest version of your web browser. The definition of spyware is flexible. Antispyware software is built into most internet security suites. If you use a security suite, check to see what is provided with yours. If it doesn't have antispyware software then install reliable antispyware software.
Use antispyware that has been recommended. (If in doubt - do an internet search for a product BEFORE downloading it. See if you can find any reviews or recommendations or avoidance stories.)
For more on preventing infection by spyware, see this page of my website.