Prior to putting it up for sale, I'm trying to wipe the Hard Drive of a PowerBook (15" / 1.67 GHZ / 2GB RAM) but I'm having no luck using my OS 10.4 install DVD. When I set the "Startup Disk" in the preferences to use the DVD, the computer spins up for a while, then hangs with a blue screen. If I hold the shift key when starting, I get a Kernel Panic. I've tried several times each way. The computer starts up just fine using the hard drive. I've tried resetting the PRAM. No joy. I've tried older versions of OSX install cd's (10.2 / 10.3). No joy. I've used the install DVD/cd's to re-format other laptops, so I know they work. The problem appears to be with this computer only. But I'm out of ideas. Any thoughts?