I wanna defrag and fix the errors on my startup disk... How do I do this? I "thought" I read somewhere that I can startup from a firewire external.... mmkay... I bought an external firewire/usb case and put in an extra WD 45gig drive that I had...... I insert my OSX install disk, blah, blah, blah.. the computer restarts.... but when it came down to install the OS, my firewire drive had a big red "!" and I couldn't install....... Is there something that I'm doing wrong? Does it have to be a firewire ONLY box, not both?