Install limit problem

hi there, i have a new laptop i want to install NIS  on to ,however i already have it on two pc`s in the house and i have a faulty pc upstairs  NIS might be installed on , but i can`t get the thing to boot up so i can check, anyway i tried to install NIS on the new laptop but it says i have reached my install limit which is 3 so it won`t allow me, how do i get round this because it looks like the pc upstairs is toast and i may not be able to uninstall NIS online to let the server know.