Rogueware refers to software that tries to advise users that their security or performance is underperforming and offers to rectify the problem. They employ this scare tactic in order to get people to part with their money to purchase licences for the Rogueware, hence why it is often also refered to as Scareware. Most of the time, scareware is useless and in actual fact can do more harm than good.
Recent Rogueware has been shown to try and uninstall well reputed brands of anti-virus, -malware or -adware software. This can have a disastrous effect as it then leaves the user believing they are protect and are free to perform their usual computer or internet activities, when in actual fact they are more at risk than ever before.