I want to put some parental control software on our two PC's which are both used by our children. Something which is free to home users. I have downloaded K9 (which I saw mentioned on another thread) but can only install it on one PC as the same licence key cannot be used on both. Is the only way around that to sign up with another email address? It's not that I don't trust my children, but I don't trust others who my children may come into contact with whilst onthe PC.