when i tried to switch to root user with the code line "su root", he ask what is root password.
so i tried my regular user password she didn't work, then i tried again but this time i didn't wrote any password and it's does not work like the first try
so i used, "sudo passwd root".
he wanted a now unix password and after that to return the new unix password.
after that i used su ****(my regular user name) and then again "su root", then i enter the root password and it's work excellent.

i read your link early today, when people from the ubuntu channel irc help me with this problem.
after i told him that i tried to open a script and install him and i don't have access because i don't root they told me that there is two solutions:
1:
sudo ./install ******
2:
sudo passwd root
and then su root, to switch root user.

i know that if i use root user directly i can damage the system and it's not recommended, i read the link information.

i didn't know that before, the technical helper from netvision didn't succes help me and pass my problem to a elder technical helper, i decide to find a solution and return to netvision to finish to install this script.
now i can return to the technical help (netvision) and connect the ubuntu to the internet and finish to installation him finally.



good night it's 4:09 am now.