I have a friend's 17" iMac G5 over at my house right now because it won't boot. After running Apple Disk Utility, we think there's something wrong with the hard drive. Disk Utility couldn't repair the problem, so I enlisted the help of TechTool Deluxe. I ran the tests the first time without doing a surface scan, and it couldn't repair it. Now it's scanning the surface and maybe we'll have better luck. Any ideas on another application I could try before we send it in?