So here's the deal - mom & dad's iMac G4 (17" 800MHz Superdrive) has been performing miserably for a while. Running disk utility and TechTool pro both tell me that the hard drive needs to be repaired - and neither of them are able to do it. I figure it's probably best to just go ahead and replace the drive altogether, to extend the life of the machine and be able to load them up with a fresh copy of Tiger to breathe new life into it. Two questions - I see that the machine uses an UltraATA 5,400 rpm drive - but I can't find any documentation to tell me if that's an ATA 100 or ATA 133. What is the technical distinction between the two? Which do I need? Second, regarding installation...I'm assuming this machine is tricky enough that I'm better of paying a professional to do it. I've done the standard RAM installation, and switched out drives in an iMac G5, but this booger isn't quite as user accessible. Any stories for or against trying it myself?