Hi, I'm hoping that I'm posting in the right place here. I've just bought my sister an external hard drive for her g4 imac. Its a 400g WD hard drive, I formatted it using a friend's mac and it worked fine, but her machine wont recognize it. Its not showing up in disk utility. She's running OS X and the hard drive has its own power supply. I really don't know enough about macs to be able to sort it. If anyone knows what I'm doing wrong it would be a great help. Thanks.