each time the infected program runs (internet). Cluster infectors modify the file system so that they are run prior to other programs. Unlike file infectors, they do not actually attach themselves to programs (internet). Macro viruses are word processing documents that can use macros like Microsofts auto-execution macros to run another type of virus to help it spread. System infectors are computer operating systems that typically set aside a portion of each disk for code to boot the computer. This section is called a boot sector on floppy disks or a master boot record (MBR) for hard disks. System infectors store themselves in this area and are invoked whenever the disk is used to boot the system. In all circumstances, someone must execute a virus, usually ignorantly, in order to spread. Two ways in which this occurs include booting from an infected floppy disk or running an infected program. System infectors are loaded each time an infected disk is used to boot the system. This can happen even if a disk is not equipped with the files needed to truly boot the computer, as is the case with most floppy disks. With Personal Computers (PCs), the first infection typically occurs when someone boots or reboots a computer with an infected floppy accidentally left in the disk drive (Cohen 46-47)Computer related vandalism will never be stopped altogether, but a computer can be safe with the right precautions....
