I had a perfectly great working powerbook g4. I was trying to get it ready to send off to a new owner. I went into single user mode, and typed in this /sbin/fsck -y [Enter] /sbin/mount -uaw [Enter] rm /var/db/.applesetupdone [Enter] reboot [Enter] My computer came back with error messages saying Volume Check Failed. It will not boot now when turned on. It just comes to apple screen with twirling icon, and then shuts down. I don't know how to reverse what I did. It was working perfectly. I do not have os disks, as I bought it resale also. I have had it for 6months with no issues. I am freaking out!!! I can't do a safe mode boot. I did get it to boot up as if it was brand new. Put in all info, thought it was fixed, then when it said to restart so that the changes could take place, it went back to not booting up. Spent 6 hours looking and trying everything. Any help???