The invention provides a method for purifying silicon which comprises a step of blowing a treating gas generated by reacting carbon with an oxidized gas into a molten silicon, as well as silicon produced by the method. A password module stores the power-on password for a blade server. The present invention may correctly identify whether a telephone call is a number-falsified telephone call. When the second instruction is given, the power is determined based on lapsed time from the first instruction detection to the second instruction detection.