A friend purchased a new 17" 1.8GHz G5 iMac a couple of weeks ago. The startup chime does not sound on every restart or starting from shutdown, sometimes it does and sometimes it doesn't. He reset the Pram and ithe chime behaved normally but he called me last night and said it did not sound after restarting when he downloaded the latest security update. Other than this he says the iMac is working perfectly. Is this something to be concerned about?