Anti Virus Protection

Here is a list of different types of viruses:

Boot Sector - A Boot Sector Virus infects the system area of a floppy or hard drive, or the part that is accessed when your computer is first turned on. Infection usually occurs when booting from an infected disk.

File Infector Viruses - Most of these viruses reside in the memory of a computer and infect programs' .exe and .com files.
Master Boot Record(MBR) Viruses Similar to a Boot Sector viruses, these viruses infect the Master Boot Record and prevent your PC from booting.
Multi-partite viruses - These viruses infect both the boot record and program files.
Macro viruses - Macro Viruses are prevalent in corporate environments where office applications are used, usually Microsoft Office(Word and Excel). They use a program's code to infect data files.
Trojan Horse Viruses - These viruses do not replicate themselves. Instead, they often pose as a harmless file that is downloaded from the web or from an e-mail attachment. These programs can result in the theft or destruction of data files. This type of virus is commonly picked up from peer to peer file sharing programs.
Worms Viruses - Worms replicate themselves without using a host file and can spread very quickly across the internet by releasing documents it has infected