A bots sometimes called a worm; it is a software which takes control of your computer system. These are software programs intended to take control of your PC. They are deployed using very stealthy techniques to attack and remain hidden once they get implanted.
They tend to communicate using peer to peer method using internet. This makes it really hard to find them. When making connect they do not use DNS or send strings which can be easily read by humans, rather they encode the message.
These worms stay dormant and do nothing for a period of interval and then suddenly jumps to actions like sending spam or phishing, password theft and other sneaky things.
Few things you can do to prevent such attach is.
Scan your computer using Norton antivirus.
Place a firewall and block unwanted traffic
Regularly update windows or any other operating systems you have.
Block outbound traffic at port that can be used to make outside connection.
