Viruses

Prior Knowledge: i know that viruses are a flaw that the computer allows to enter and it may ruin it or steal information about it. 

1. Questions: Why were they created?
2. What are they made of?
3. What is the purpose of the viruses?
4. who created the first virus? 
5. Was it on purpose the virus? Or was is a mistake. 

Things learned: 
What is a computer virus?
a  computer virus are small program software that are used to interfere with the computer operation. 
What do Computer virus do?
A computer virus might corrupt or delete data on your computer, use your email program to spread itself to other computers, or even erase everything on your hard disk. They normally come from email attachments so you must verify first who send it. Also virus can come from downloads or images. 
How to know if you have a virus:

• Computer running slow
• Computer stops responding or freezes often. 
• Computer crashes and restart every few minutes 
• Your computer restarts on its own and then fails to run normally
• Applications on your computer don't work correctly
• Disks or disk drives are inaccessible
• You can't print correctly
• You see unusual error messages

You see distorted menus and dialog boxes

Types of Virus:

• Trojan Horse: It looks like it is going to have  a useful and desired function.  Secretly the program performs other, undesired functions. A Trojan Horse neither replicates nor copies itself, but causes damage or compromises the security of the computer. A Trojan Horse must be sent by someone or carried by another program and may arrive in the form of a joke program or software of some sort.
• Worms: The worm may do damage and compromise the security of the computer. It may arrive via exploitation of a system vulnerability or by clicking on an infected e-mail.
• Rootkit:undetectable virus which attempts to allow someone to gain control of a computer system

Who created the first virus?

Elk Cloner used the boot sector to infected the desktop. 

How to remove a virus?

There are virus scanners and programs that do that for you like the one of microsof

Reflection: 
After all the research I have done I realize I should be more carefu; with the things I do in my computer like downloading music or movies, this may get my computer infected. Afterall I find out this topic really interesting. 
Still one question: Why did the created it? 

http://www.microsoft.com/security/pc-security/virus-whatis.aspx
http://antivirus-software.topchoicereviews.com/types-of-viruses.html
http://answers.yahoo.com/question/index?qid=20081102200402AAoxPsY