Believe it the same thing happened to me! I went on the capooter(Ca-Poot-Er is my special way of say CPU) and it was really slow. So,I went to see what could be causing it by doing a virus scan with Norton. When it was done it said in the EVIL folder bin area as I call it "Trojan Horse". The horse pic is the trojan package side effect that sort of tips off the problem to the user. The trojan it self is not virus it is a package loaded with viruses. The reason why no one else has had a problem is because the trojan does'nt activate at first. The viruses activate from a file being opened. It activates then. It can do many stupid things when it does. You know what just read the rest here right from wikipedia:
Trojan Horse(computing)
In the context of computing and software, a Trojan horse, or simply trojan, is a piece of software which appears to perform a certain action but in fact performs another such as a computer virus. Contrary to popular belief, this action, usually encoded in a hidden payload, may or may not be actually malicious, but Trojan horses are notorious today for their use in the installation of backdoor programs. Simply put, a Trojan horse is not a computer virus. Unlike such malware, it does not propagate by self-replication but relies heavily on the exploitation of an end-user (see Social engineering). It is instead a categorical attribute which can encompass many different forms of codes. Therefore, a computer worm or virus may be a Trojan horse. The term is derived from the classical story of the Trojan Horse.
In the field of computer architecture, 'Trojan Horse' can also refer to security loopholes that allow kernel code to access anything for which it is not authorized.
