new account ....how i...help..

[Darkkel]

You have to IP ban them, I'm not really sure how it works, but when you IP ban them you ban the IP of their actuall computer or something, so they can't make a new account; you would still be banned.

IP Ban = Fail. You can change your IP as you change your clothes.
MAC Address ban = Win. Can't be changed, or hardly. Some people gonna cry "You can change your network interface MAC ! DUMB NUB !". Modem's MAC can't be changed, face it.
Steam ID ban = Half-win (depends if they're rich/dumb enough to have several accounts)