No it's not. It means that the inexperienced can't terminally mangle their operating system like they always do in Windows. It is also one of the things that makes Apple OS X so much more secure than the virus-prone Windows.
System Preferences provides all the options you should beed.
What are you trying to accomplish? A Mac is not a PC. There is no BIOS. If you can tell us what you want to do, we can advise you how to do it, but we can't tell you anything more than what Niel and Klaus have said if you don't.