Viruses

What I know about viruses: 
I know that viruses are bad for your computer, and that they mess up how the computer works, but I don't really know what they do or how they get on your computer. 

Questions: 
How do viruses get on your computer? 
What types of viruses are there? 
What can a virus do to your computer? 

Helpful links: 
http://www.smithsonianmag.com/science-nature/Top-Ten-Most-Destructive-Computer-Viruses.html 
http://www.howstuffworks.com/virus.htm 
http://home.mcafee.com/virusinfo/top-viruses 
http://www.webroot.com/En_US/consumer/articles/computer-security-threats-computer-viruses 

8 Things I Learned: 

• There was a virus called the Conficker Virus which infected millions of people's computers that could steal financial and other information. Although it steals information no one actually knows what its original purpose was. 
• The Poison Ivy virus is extremely creepy. It allows the hacker to take complete control over the manipulated computer. The hacker can record audio and video, us the webcam, and manipulate the computer's content. It's scary. 
• a virus is a piece of software that attaches itself to other softwares, and when those softwares run the virus runs too, allowing it to spread and attach itself to more softwares. 
• Trojan Horses are computer programs that say they do one thing but actually do another. (i.e. pretends it's a game but actually damages your computer.) 
• I looked up top viruses tracked by McAfee and all of them were Trojan Horses and Viruses 
• A virus can find you if you share music, files, and photos with other people on the internet 
• Viruses can make you unable to do any internet activity, delete your files, damage programs, cause computer crashes, and reformat the hard drive of your computer. 
• computer viruses really started in the 1970s, even though theories had been made earlier 

How this topic relates to my life: 

     I use the computer all the time, and sometimes I click on things that I probably shouldn't. I'm sure I've clicked on Trojan Horses. By researching about viruses I can be more aware of what is safe and what I should stay away from on the computer. I learned a lot of things that I wasn't aware of before today. 

Questions I still have: 

Was the creeper virus the first ever virus invented? 

How much money is involved in the underground virus-making/hacking community? 

What was the Conficker Virus originally meant to do? 

How do viruses infect so many computers in such a short amount of time?