What is spyware ? How does it effect your computer ? What is the relation between malware and spyware ?

What is spyware ? How does it effect my computer ? What is the relation between spyware and malware ? How does it enter my computer ?
        Spyware is a type of malware that can be installed on computers, and which collects small pieces of information about users without their knowledge. The presence of spyware is typically hidden from the user, and can be difficult to detect.
   It can be installed through the browsers very easily.It tries to install plugins into your browser or install harmful softwares into your computer without your permission,you may not know it. 

What is anti-spyware ? How does it protect your system from spyware ?
      Anti spyware is the software that protects your pc from spyware.There were many softwares available to do so , but most of the users are confused of what is best and what are free to use , i suggest there were some softwares that protects your pc from spyware.To know more about them click here.