What does Anti-Virus mean ?

1. What is the meaning of Anti- Virus?
2. How does it help users?
3. What are the advantages of using it?
4. What are the different Anti-Virus applications?
5. Which is the best to be used?
6. Does Anti-Virus really guarantee for computer's safety?
7. How could this application affects our daily routine?
8. Is everybody requires to have it?
9. Where can we get this? Is this free?
10. How can we get it?
