administrative account over internet connection?

I am a newbie. How do I shield the administrative functions of my O/S (Knoppix 4.0) over the internet. I know it has something to do with which user I am logged in as. I don't know how to create a different user, so that the administration account is not vulnerable over the internet.
Before coming across all the warnings, not to install KNoppix to the HD, I did. I'm using an old Pentium II box, that had corrupt win 98 and is intended as a handme down to the kiddies. Familiar with corrupted registries, I had some experience with wiping partitions. With the help of many online articles, I've had a very pleasant experience with the Knoppix installation. I have to say, I'm pretty excited about not using Windows. (Later, If it will help anyone else, I will document my experience.)
Not sure if it was going to work, I only created one user upon installation. What do I do now?
This is my first experience with Linux (or Debian?). Any help would be appreciated
Thanks,
Zekesax

Default Knoppix root password is blank (not set anything). So first set your own password for root, then exit out of root. Knoppix is another buit in user, which is not root. And I think it will be safe once you are browsing net. I hope this is what you wanted!!