Rogue anti-virus programs usually appears in the form of a fake Windows warning on your computer system that reads something like, you have a specific number of viruses on your computer (usually in the hundreds) and that this software has detected those viruses. To get rid of these viruses, you’re prompted to buy the full-version of the antivirus software (which is really rogue antivirus software).
The good news is that you probably do not have a computer that is infested with hundreds of viruses as the rouge software claims. The bad news is that the rogue antivirus software itself is on your computer and you must remove it. Removal is hindered as rouge software can lock the control panel and the the Add/Remove Programs function to prevent you from removing it easily.
Rogue Anti-Virus Software Explained
By Vangie Beal, Last updated April 24, 2009