If you use the internet, you have probably been infected with a virus, trojan or spyware. According to the SANS Internet Storm Center, the average unprotected PC is infected within 20 minutes of normal internet usage. Many people want to know what they did to get infected. Unfortunately, usually it was just one wrong click.

Here are the top reasons people get infected and how to prevent these common internet security threats.

10. Exchanging files in chat rooms.
You should never download files from sources you don