text: what is trojan horse virus and its effects ?   a program that either pretends to have, or is described as having, a set of useful or desirable features, but actually contains a damaging payload. most frequently, the usage is shortened to "trojan". trojan horses are not technically viruses, since they do not replicate.  in short, it's a program that seems innocent, but allows someone to be able to either transfer information or provide access to your computer, it can also transmit information