A computer virus is a program designed to harm or cause harm on an infected computer. Its spreads through e-mail attachments, portable devices, websites containing malicious scripts and file downloads. A computer virus attaches itself to the host files and always activate whenever you open the infected files. The virus can replicate itself and then infect the other files on your computer causing more damage. Below is a list of different types of computer viruses and what they do.
Macro Viruses
These viruses infect the files created using some applications or programs that contain macros such as doc, pps, xls and mdb. They automatically infect the files with macros and also templates and documents that are contained in the file. They hide in documents shared through e-mail and networks.
Macro viruses include:
Relax
bablas
Melissa.A
097M/Y2K
Memory Resident Viruses
They usually fix themselves inside the computer memory. They get activated every time the OS runs and end up infecting other opened files. They hide in RAM.
Memory Resident Viruses Include:
CMJ
meve
randex
mrklunky
Overwrite Viruses
These types of viruses delete any information in a file they infect, leaving them partially or completely useless once they are infected. Once in the computer, they replaces all the file content but the file size doesn’t change.
Overwrite Viruses Include:
Trj.Reboot
way
trivial.88.D
Direct Action Viruses
These viruses mainly replicate or take action once they are executed. When a certain condition is met, the viruses will act by infecting the files in the directory or the folder specified in the AUTOEXEC.BAT. The viruses are generally found in the hard disk’s root directory, but they keep on changing location.