§ This is actually about not to recover but to change to new root password with normal login. If your computer is installed with grub do this:
Reboot computer when it prompts for choosing operating system choose linux. Type 'e' to edit choose line starting with start word "kernal" type 'e' to edit, type single at the end of this line. Now press return key to come back to options and press 'b' to boot the system in single user mode. You will see it is booting normally and finally you will be at shell somthing like this "sh....$" type passwd and press enter. Voila! It prompts you to change root password, give any password and retype when prompted. It will change root password. Reboot now and enjoy root password of linux computer. This even do not require your login. A simple way to hack any linux comp. Am i raising questions on security of linux ? If your sys-ad is aware of this, believe me this will not be easy.