Boot sector viruses

the boot sector viruses is an early type of computer spreads by hiding itsel
in an invisible location on your hard drive or floppy disk.It may also be caller
system sector viruses because they attack the system sector. System or boot sector
contain programs that are executed when the PC is booted.Two types of systen
sectors exist; DOS sectors and partition sector.

File viruses

A file virus  is one that replaces a key system file on your computer.These viruses
can reload themselves every time you start your computer up. Once they're in the
memory. they can spread by writing themselves to any disk you inset into your disk.