Please verify your boot disk. Now mount the root partition. The cdrom has created a directory a for mounting hard disks. The next step is to remove root's password. Find root's entry in the file and make the second field null.
Colons are the field delimeters.
Now boot to single user mode using the hard disk. You can login as root without a password and set root's password using the passwd command. Finally, exit single user mode and let the system continue booting to multi-user mode. I recommend rebooting to single user mode first because if the system is set to not allow null passwords you may not be able to login as root with a null password in multi-user mode. The information on Computing.