Ok...I've just bought an iBook from ebay, 1.33/512Mb 12" and run into problems straightaway. Turning it on, it started a self install of Leopard (from an image on a separate partition) but on first reboot got the dreaded crash screen (attached). After a few unsuccessful restarts I decided to install Tiger (which is what I'd have done soon enough anyway with only 512 RAM) but got exactly the same crash - goes through the install but crashed when booting from the hard drive. Tried again but this time zeroed out the drive to hopefully flag any bad sectors - same result. Tried again but this time got the garbled screen, so zapped PRAM, removed battery, held power button for 10 secs - back to normal screen but still crashed at first reboot. Next, put iBook into target disk mode and ran DiskWarrior from my G5 over it for any disk errors but all appeared fine, so installed Tiger from the G5. All went well, with the G5 booting into Tiger from the iBook drive. Restarted iBook and again, crash at boot. Any ideas? The target disk install would indicate the hard drive is healthy but the iBook can't start from it - is there some hardware conflict that only occurs when booting from the hard drive? I did try booting from an Apple Service Disk (2.5.8) - which I thought was applicable to this model but it refused to launch. If it's beyond help it's a really shame because it's a great laptop.