I've scoured the net for an answer to this, but no luck so far. On startup I get the chime and the Powerbook looks like it is starting up, but there is no pinwheel and no progress. I've left it for 1/2 hour and it stayed on the grey screen. The optical drive is acting funny as well- I could only boot from Diskwarrior (not Mac OSX 10.4 Install Disc), and when I did, the screen looked like a negative, with severe pixelation (it was not because of my Universal Access settings either). I've tried unplugging and removing the battery overnight, resetting PRAM several times, attempting to start in Verbose/Single User/Safe modes (none of which work), running Diskwarrior 4.0, starting from other startup disks (no luck). There is a new HD installed and it is ok according to Diskwarrior. The machine will load in Target Disc mode and Open Firmware mode, but that's it. I am at a loss, any suggestions? I'll try just about anything!