How to get "su"

I'm trying to install firefox 3 and I can't do anything because I'm not logged in as an administrator. I see several articles about you need to be logged in as "su" but nothing telling me how to do it. Thanks.

 

alt f2
write "terminal" without quote and enter

su -
password

and now you're "root"

 

maybe i asked the wrong question. I'm trying to extract the file i downloaded and it won't let me because i don't have permissions. The last post you gave me worked, but i'm not working in the terminal.

 

If I understand you correctly you require the file manager to open with root privileges.
To do this.
Hold down the Alt key and press the F2 key.
The Run Application dialog opens.
In the window type:

Code:

sudo thunar

Click on Run.
Thunar opens as root. (Thunar is the xfce file manager)

 

my computer uses Xarchiver to do this. Is there any way i can just log onto the computer as a root so everything i do is kosher? This is incredibly frustrating for a windows guy because i can't do anything on my own computer.

 

It is not recommended to log into a Linux computer as root. Use sudo which gives you temporary superuser status.

Cheers.

 

Solved the problem with a different guide. Thanks for the help.