If you are not sure about the user name and password, what you can do is boot the system with cdrom in single user mod as below
Once system is booted, mount the root file system to /a and edit the /a/etc/shadow file and remove the encrypted password which is there after root:----:, delete the second columns assuming that each is separated by ‘:’. Then umount the file system and reboot it again as normal. You will able to logging to system as root user .
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Sorry I couldn’t see you last post
Can you check if cdrom is the alias given to CD drive? On OK prompt give devalias and check if you can get CD-ROM there