"Luckily there are ways of getting access to systems
without having the password. This is of course in a sense also a
security risk. That's why you should always be aware that having
unattended physical access to a computer system means the same as
having root access to the operating system. Unless the information
on a system is encrypted, it's only as save as the room it's in.
"The method to use to reset the password if you lost the root
(or only) password depends on the configuration of your system. But
it mostly comes down to two separate tasks:
"- get write access to the root partition - change the
password/circumvent control
"Here are some things you can try from easy to more
complicated."