Boot Sector Infectors

Boot sector infectors attack the boot program (also called a loader or "boot strap") that is stored on every bootable floppy disk or hard drive. The boot loader program is executed by the system when the PC is starts. Viruses that install themselves in the loader are guaranteed to be executed every time the system is booted and before the whole operating system is in place. This gives them full control over the system to do what they want. Boot sector viruses are most commonly spread through bootable floppy disks that are infected. As fewer and fewer people use floppy disks, and even fewer ever use them to boot PCs, this threat is becoming less important. A boot sector virus on your PC's hard drive, however, is still something to be dreaded.