What is the most typical type of trojan horse? The most typical type of computer system virus is the malware. A virus is a sort of malicious code or program that, when carried out, reproduces by inserting itself into various other computer programs, data documents, or the boot sector of the hard drive. Therefore, virus can spread throughout a network of computer systems and also cause major damage.Malware is a type of harmful software that is developed to damage or disable computers. learn more