Someone suggested I do this but I don't understand these directions. I dropped my PB and I hear clicking noises so it was suggested that I put in the second of the two OS X c.d.'s the computer came with, to see if the HD is damaged. He/she said to "hold option at boot." Does this mean press down on the "option" key before, during, or after the c.d. is put in? sorry for being so computer illiterate!