A rogue software (also known as rogueware ) is not a virus but a specific type of malware (called scareware ) that is disguised as anti-virus or anti-malware and under the pretext of cleaning up the infected computer, steal personal information and, perhaps, also seek to receive the money.
More precisely, once you download and install one of these malicious programs, it pretends to scan your computer to find a tremendous amount of viruses and / or malware, only in order to eliminate these infections, asks the user to buy program in the full version.
Once the money spent or not, not only will it not remove these fake infections but, in the meantime, will be stealing personal information, then will revise the home page and / or the search engine of the browser and turn off the real protection systems, alter registry keys and maybe even be install any adware or malware on your PC.
Unfortunately, this rogueware contract does not take much: simply clicking on the deceptive banner advertising will install the fake antivirus (or fake anti-malware) that is proposed. To avoid these problems, keeping in mind that no one can know what is or is not on your computer (before your explicit consent), and consequently never click on any kind of notice that is on the Internet.