A small number of 2GB and 4GB hard drives on Power Macintosh 7300, 7600, 8600, and 9600 computers may cause occasional system freezes. The computers with this problem have 7142 as the first four numbers in the serial number. Apple has determined that this is caused by a problem with the hard drive's firmware. It can be fixed by a "firmware upgrade utility." However, Apple is not making this utility available to the public. You will need to contact an Apple Service Provider to get your Mac fixed.