You must have remembered the messages like Trojan, worm and shortcuts.exe when you are debugging your Personal Computer using an antivirus well for many of us these are simple viruses which tends to corrupt windows or any operating system. Infact it isn’t so every virus has its own unique characteristic and tends to replicate itself once activated. Have a look to the following list;

10: Melissa

During the year 1999, a software genius named David L. Smith created a computer virus which was based on the Microsoft Word macro. The virus has its characteristics of spreading messages through electronic mail. The name proposed for the virus by Smith was Melissa; accounts suggest that it was the name of an foreign dancer from Florida.  The Melissa computer virus persuades recipients into opening a document with an e-mail message like “Here is that document you asked for, don’t show it to anybody else.” Once triggered, the virus duplicates itself and propels itself out to the top 50 people in the recipient’s e-mail address book.

9: ILOVEYOU

Only after a year of the creation of Melissa virus another digital hazard came into existence from the area of Philippines. The Threat or Virus was in the form of Worm and it was a standalone program having the capability to duplicate itself. The name given to this worm was ILOVEYOU. During the initial stages the virus travelled through email messages similar to the way Melissa travelled. The message says that the email is from a secret admirer and wants to convey you his/ her feelings. The original worm had the file name of LOVE-LETTER-FOR-YOU.TXT.vbs. The vbs extension pointed to the language the hacker used to create the worm: Visual Basic Scripting.

According to anti-virus software producer McAfee, the ILOVEYOU virus had a wide range of attacks:

• It copied itself several times and hid the copies in several folders on the victim’s hard drive.
• It added new files to the victim’s registry keys.
• It replaced several different kinds of files with copies of itself.
• It sent itself through Internet Relay Chat clients as well as e-mail.

8: The Klez Virus

The Klez virus manifested a new way for computer viruses, raising the bar high for those that would go after. It debuted in the year 2001, and deviations of the virus overwhelmed the Internet for numerous months. The basic Klez worm infected a victim’s computer through an e-mail message, duplicated itself and then sent itself to people in the victim’s address book. Some variations of the Klez virus carried other harmful programs that could render a victim’s computer untreatable. Depending on the version, the Klez virus could act like a normal computer virus, a worm or a Trojan horse. It could even disable virus-scanning software and pose as a virus-removal tool. Source: Symentec