lost su password

Definition: SU: Switch User (Unix) sometimes they call super user

Many distro does not create a root user by default.
There's too many description of su, for example:
-, -l, --login
make the shell a login shell
-c, --commmand=COMMAND
pass a single COMMAND to the shell with -c
-f, --fast
pass -f to the shell (for csh or tcsh)
-m, --preserve-environment
do not reset environment variables
-p
same as -m
-s, --shell=SHELL
run SHELL if /etc/shells allows it
--help
display this help and exit
--version
output version information and exit

but, what happens if you lost a su password? It's happen to me until I got the answer of all the problems. It has two alternative way:

su passwd
sudo passwd

and on my pclinuxos 2007, it work with sudo passwd. No, what ever I want to open (eg: synaptic package manger, installing software etc) I must put sudo passwd on terminal. Everything will working on terminal only.

If everybody knows how to change su password, please tell me. It's really hard when everytime I want to use synaptic, I must open it with terminal.

THIS TIPS ALSO DOESN'T WORK..

""$ id ""uid=1001(someuser) gid=0(wheel) groups=0(wheel)
""$ passwd ""Changing local password for someuser ""Old Password: ""New Password: Retype New Password:

To change root's password:

""$ id ""uid=1001(someuser) gid=0(wheel) groups=0(wheel)
""$ su ""Password: ""# id ""uid=0(root) gid=0(wheel) groups=0(wheel), 5(operator)
""# passwd ""Changing local password for root ""New Password: ""Retype New Password:

to change another user's password:

""# id ""uid=0(root) gid=0(wheel) groups=0(wheel), 5(operator)
""# passwd someotheruser ""Changing local password for someotheruser ""New Password: