A computer virus has a similar appearance as an ordinary computer program, however, they are designed to spread from one computer to another and can interfere with computer operation. A virus’ purpose is to damage data, destroy other programs, and in most cases interrupt the normal operations of a computer. A virus can corrupt or delete data on your computer, use your e-mail to spread itself to other computers, or even erase everything on your hard disk.

Viruses can be disguised as attachments and can be hidden in e-mail messages, instant messaging messages, illicit software or other files or programs you might download. Below is a list of some of the different types of viruses that can infect your computer. It’s important to select a virus scan and removal program capable of dealing with this variety of viruses.

Boot Sector viruses: A boot sector virus can infect diskettes and hard drives. All hard drives and disks contain smaller sections called sectors. The first sector is called the boot. The boot carries the Master Boot Record (MBR). MBR functions to read and load the operating system. So, if a virus infects the boot or MBR of a disk, such as a floppy disk, your hard drive can become infected. Once your hard drive is infected all diskettes that you use in your computer will be infected. Boot sector viruses often spread to other computers by the use of shared infected disks and pirated software applications.

Program viruses: A program virus becomes active when the program file (often with extensions .EXE, .COM, .BIN, .OVL, .DRV) carrying the virus is opened. Once active, the virus will make copies of itself and will infect other programs on the computer.

Multipartite viruses: A multipartite virus is a hybrid of a Boot Sector and Program viruses. It infects program files and when the infected program is active it will affect the boot record of your computer.

Stealth viruses: A stealth virus can disguise itself by altering its file size or concealing itself in your PC’s memory preventing itself from being detected by anti-virus software.

Polymorphic viruses: A polymorphic virus is a virus that can change its signature (also known as binary pattern) every time it multiplies and infects a new file. By changing binary patterns, a polymorphic virus can be hard to detect by anti-virus programs.

Macro Viruses: A macro virus is programmed as a macro embedded in a document. Many applications, such as Microsoft Word and Excel, support macro languages. Once a macro virus gets on to your computer, every document you produce will become infected. This type of virus is relatively new and may slip by your anti-virus software if you don’t have the most recent version installed on your computer. .

Active X and Java Control: Some users do not know how to manage and control their web browser to allow or prohibit certain functions to work, such as enabling or disabling sound or web pop ups. This can leave your computer open to attacks from unwanted software or adware found on the Internet.