What is the best and free anti-virus program for my computer?

I need a free and brilliant anti-virus for the computer as i am on it 24/7. It need it to be as good as norton or something. Probably one that removes spyware, malware, virus, trojans, worms, etc. any ideas please?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).