While the Internet has ostensibly become a safer place (people know more than ever before about safe surfing habits and the browsers are always trying to stay ahead of the malicious coders), there is still no excuse for surfing the web without an antivirus program. Antivirus software is your last line of defense against the many harmful programs out there that can destroy your computer.
Most good antivirus programs come with a scanning function. With this, you can do a thorough scan of your computer and make sure you aren't infected with anything that might be breaching your security or causing your computer to slow down.
Every antivirus program has its own ways in which it responds to threats or viruses found on a computer. It may quarantine the infected programs in case they are not really viruses, but rather something you need for your computer to run smoothly. Usually, it will ask the user whether or not he wants to delete the infected programs.
The main purpose of antivirus software is, of course, to protect the computer from getting a virus. It does this by scanning downloads and attachments for viruses, and by running in the background when the user is surfing the Internet. Should the user come across a virus, the program will warn the user and give her the option of getting rid of it before it infects.
The best antivirus programs are equipped and updated to protect the user against spyware and adware, two scourges of the Internet world. These malicious programs enter a computer through the browser, usually as a result of pop-up ads or a bad Internet site. The antivirus program will usually block these pop-up ads, but if one gets through, the program will warn the user and let him eliminate the threat before it attacks the computer.
How It Works
Most antivirus programs work through signature detection. The program keeps a (often updated) library of malicious programs and viruses. Whenever the software comes across a piece of suspect software, it will compare the signature on the file to its database. If it matches a piece of malicious software, the program will act accordingly.