Am trying to install OS 10.4.7 on an IMac that has OS 10 on it. Following the disk directions, I boot-up with Disk1 and keep tapping Ctrl. However, I get error mesage across screen saying that driver for power mac 4.5 not installed. Therefore, I cannot install the OS. Any help would sure be appreciated, as I'm trying to do this for a friend of a friend. While I can handle myself around PC's, am at a loss with a Mac. Thanks.