A Trojan is a malware that pretends to be a useful application or comes bundled with one. After being secretly installed into computer, Trojan horse hides from the unsuspecting user and it is quite difficult to detect and disable. Threat usually carries a destructive payload which depends on intensions of a scammer. Some of them provide the attacker with unauthorized remote access to a compromised computer, infect files with additional parasites and damage the system. The most obvious sign of Trojans is the infections of other types of parasites, like starting seeing popups or PC slowing down.