Root account

Accessing the Root Account on the gPC/gOS
One of the first things you will probably want to do upon boot up is to lock down the root account. By default, the root account does not have a password, which means anyone with access to the default gOS account can quickly gain full control over the operating system and essentially do anything they want. In order to prevent this, you have to set the root password to something you can remember. To do this, click the green leaf in the corner, select "Run Command" and type in "xterm." This should load a terminal window similar to [omitted].

Once the window opens, type "sudo passwd root." The computer will prompt you for the current account password, after which it will ask to "Enter new UNIX password." Type in the password you wish to assign to the root account and enter the same password again for a confirmation. Congratulations — you now locked down the root account.

Or

You can do the same by pressing Ctrl + Alt + F1 and login as normal user account and type as "sudo passwd root" and set password that you need.

NOTE

You will not be able to log into the initial GUI screen using the root account — and this is a good thing. There is no reason to be using the root account on your gPC for normal everyday activities. In fact, surfing the internet while logged in as root is extremely risky and should never be done for security reasons.

Unfortunately, the system is still insecure because anyone can enter what is called "single user" mode during the boot up process and change the root password. So, to prevent this, we need to password protect the program responsible for booting the operating system, grub. To do this, perform the following:
 * 1) In terminal window, type su root.
 * 2) Type in the recently created root password.
 * 3) Type "grub" to access grub program.
 * 4) Type md5crypt, then enter in your grub password (it can be the same as your root account password).
 * 5) Record the returned results (Figure 8).
 * 6) Type "quit."
 * 7) Type "pico /boot/grub/menu.lst."
 * 8) Scroll down to password part of the file and enter the following "password --md5 ."
 * 9) Hit the Ctrl-O followed by Ctrl-X to save and exit the pico text editor.

At this point your machine is fairly secure. There are other ways to gain access to the root account, but these are beyond the scope of this article.

source: verbatim from http://www.informit.com/articles/article.aspx?p=1146503&seqNum=5