If you’re browsing the web and you see a security warning, beware. Cybercriminals use fake security warnings (also known as “rogue security software”) to steal personal information or to charge you for a program that doesn’t work.
You should only download software from a reputable source. Microsoft Security Essentials, for example, is a program that can help protect your computer. Download it for free.
To watch a video about the extent of the problem and what Microsoft is doing about it, see Rogue Security Software: Scamming for Money.