Aporte original por: mayer ,
It you installed from a retail 10.5 disk, reboot from it and hold down the C key. Go to the installation procedure, on the second page the pull down menu will appear. From under Utilities go to change password and change it. Next I would run Disk Utilities and see if you have a problem. At this point i would return to the installation and do a full re-install. When the installation is complete it should restart on its own and go to the set up page. If you ever need to eject a disk manually, shut down the computer by pressing and holding the power button, Upon restart hold down the mouse and the disk should eject.