A virus is a program that spreads itself by infecting other programs on the same computer or laptop. Viruses can do serious damage, such as erasing your files or your whole disk. However, they may just do silly things like pop up a window that says “Ha ha you are infected! Please download this program to help you clean the virus”. While you download the program, you are actually downloading the virus. True viruses cannot spread to a new computer without human assistance, such as if you trade files with a friend and give him an infected file (such as on a thumb drive or by an email).

Example of Virus:

Word Maco- Attach and spread through Microsoft Word and Excel files

Subject: Important Message From ” Application. User Name Message “Here is that document you asked for … don’t show anyone else “ Attachment
Or
Subject: Resume for Janet Simons

Resource:

“Computer Viruses: What is a Computer Virus? | Microsoft Security;.” 2 Dec 2008 <http://www.microsoft.com/protect/computer/basics/virus.mspx>.

“Trojan Horse or Virus?.” 2 Dec 2008

<http://www.irchelp.org/irchelp/security/trojanterms.html>.

“viruspre.pdf (application/pdf Object).” 2 Dec 2008

<http://xys.ccert.edu.cn/reference/Worms/viruspre.pdf>.