What can be done to stop my addiction to computer and start to become productive?

Brain: Most addicitons are a brain thing. Certain parts of the brain produce pleasure and these get very sensitized so a very small particular stimulus will set them off. If you really want to stop an addiction, stop the action completely and do - rpeat do - something different. Eventually the urge dies down. But a little of the same thing will start things up again - even a long time later.