I'm not quite clear on what you managed to do. I recommend, however, that you learn a little about the multi-user environment concept around which Unix and its descendants have been built.
Linux, as a Unix-compatible OS, is designed as a multi-user OS. That means that it runs different user accounts in different "user spaces". That's a fancy way of saying that it keeps what one user account does separate from what another user account does.
Normally, you want to use your standard user account. Sign in as your standard username, whatever that is, and use the computer in that manner. When you need to do something that requires administrative permissions, you either sign out and sign back in as the root user (username "root"), or you type "su" at the command line and enter the root password when prompted. If you signed out and back in, do so in reverse when you're done with whatever administrative tasks you're working on (by signing out of root and back in under your standard user account). If you used "su" to gain administrative permissions, you should be able to simply type "exit" and hit the Enter key to get out of the administrative mode.
This is important for a number of reasons, but the biggest one to remember is this: It helps keep your system secure. The fact that you can't do certain things when not signed in as root is a GOOD THING, because that means that crackers, trojans, computer virus infections, and other challenges to your system's security also cannot do these things without accessing the root account. If you're just signed in as root all the time (or have administrative capabilities assigned to your standard user account by default), malicious users and malicious code will find it easier to execute harmful routines on your computer without your express permission.
Even if you're on a stand-alone computer that isn't even connected to a network, you should stick to this habit of keeping administrative and non-administrative use separate: it's just a good habit to be in.
It is in large part because of the lack of separation of user spaces (and even XP Professional doesn't fully separate the user spaces the way Linux and other Unix-compatible OSes do) that Windows computers are so much less secure by nature than a well-maintained Linux computer is.
