How I discovered "IT"
I never knew a thing about computer until I was thirteen years old. The first time I ever touched a computer was when my family moved to Canada for a while and bought a brand new Toshiba Satellite in 2002. At that time all I did was play games on sites such as cartoonnetwork.com ytv.ca, which were all sites that had mini flash games and funny videos. No one in my family knew how to use a computer well and how the internet operated, plus we had no Anti Virus program.
Over a course of few months our computer got slower and slower. Sometimes it would not even load the new webpage. It got to the point where it tool literally 30 to load the desktop. My parents got mad because the computer was so slow that it was not even operating any more. We took it into a computer technician and had it fixed for $30.00 which 2 month later my friend told me he could have done it for free and under 2 hours. I asked him how could you have fixed it and what was wrong with it.
The problem did not have anything to do with any hardware stuff but just it was overloaded with "cookie" and "Malware" which is another word of a computer virus. What these files were doing to my computer was using my computer to attain personal information and sometimes use my computer to store illegal files in my computer. All I had to do to fix this problem was just re-boot my computer to factory setting and everything in my computer goes back to how I got it when I first time opened the box and turned it on.
Types of Malware
There are Many times of Malware out there but I would like to explain the BIG ones that is most commonly attack computers
Trojan Horse: A Trojan is another type of malware named after the wooden horse the Greeks used to infiltrate Troy. It is a harmful piece of software that looks legitimate. Users are typically tricked into loading and executing it on their systems. After it is activated, it can achieve any number of attacks on the host, from irritating the user (popping up windows or changing desktops) to damaging the host (deleting files, stealing data, or activating and spreading other malware, such as viruses). Trojans are also known to create back doors to give malicious users access to the system.
Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate. Trojans must spread through user interaction such as opening an e-mail attachment or downloading and running a file from the Internet.
Worms: Computer worms are similar to viruses in that they replicate functional copies of themselves and can cause the same type of damage. In contrast to viruses, which require the spreading of an infected host file, worms are standalone software and do not require a host program or human help to propagate. To spread, worms either exploit a vulnerability on the target system or use some kind of social engineering to trick users into executing them. A worm enters a computer through a vulnerability in the system and takes advantage of file-transport or information-transport features on the system, allowing it to travel unaided.
Virus: A computer virus is a type of malware that propagates by inserting a copy of itself into and becoming part of another program. It spreads from one computer to another, leaving infections as it travels. Viruses can range in severity from causing mildly annoying effects to damaging data or software and causing denial-of-service (DoS) conditions. Almost all viruses are attached to an ".exe", which means the virus may exist on a system but will not be active or able to spread until a user runs or opens the malicious host file or program. When the host code is executed, the viral code is executed as well. Normally, the host program keeps functioning after it is infected by the virus. However, some viruses overwrite other programs with copies of themselves, which destroys the host program altogether. Viruses spread when the software or document they are attached to is transferred from one computer to another using the network, a disk, file sharing, or infected e-mail attachments.
Bots: "Bot" is derived from the word "robot" and is an automated process that interacts with other network services. Bots often automate tasks and provide information or services that would otherwise be conducted by a human being. A typical use of bots is to gather information or interact automatically with instant messaging (IM), Internet Relay Chat (IRC), or other web interfaces. They may also be used to interact dynamically with websites.
There are countless amount of viruses spreading around the globe through the Internet a day. Not every one can protect them self from these malwares. All malares are different and depending on how good the programing was to create the virus you could catch it before it does any harm or it could slip past your firewall and eat away your computer files until it becomes unrepeatable. There are many ways one could protect them selves but Microsoft says that the best way to do it is having common sense.
This video here also helps a user how Anti-virus work and what you should do about it.