I am having these annoying CyberDefender Ads pop-ups on my laptop. The problem occurs after I accessed a link sent by a friend on Yahoo messenger. The screen suddenly goes black and the computer reboots on itself. After Windows started, the desktop started to show various messages containing different alerts saying that my computer is infected. Is CyberDefender another type of rogue application or just a legitimate application that promoted excessively? Can you please tell me how to remove it?