Hi, I've been working on restoring a couple of late G4 17" Powerbooks (5,5, A1085), and I have one that does not find the drive on a reboot, but finds it OK on a cold boot. (Got these as basket cases so I have no idea about their history). If you reboot from the desktop, you see a flicker as the machine finds the drive, then the dreaded flashing folder with a question mark. It had a similar problem installing the OS--until I figured out that I had to start it cold with the O/S disk in place. I started with 10.4 for PPC, and then used a retail copy of 10.5 for installs. Things I have tried: Imaged drive (CC Cloner), fresh build (more than one drive), different memory (long shot). Set PB in Target Mode and ran Drive Utility to check. (Another machine seemed to fix itself after this--but it may have been a different problem) Had the HD cable off multiple times, examined the cable/mobo connection pretty carefully. Things I don't have: Original install disks (I have one set for G4 that works with the 1.3ghz, but not the 1.5 or 1.63) An extra known good drive cable--what I have at this point is one other that is known bad... Things I don't know: Was there a firmware upgrade for these machines? Does it matter that I am using non-Apple (Hitachi/IBM) drives? Any thoughts on what might be the problem?