A huge advantage that Unix and Linux operating systems have over Windows is that Unix and Linux do a much better job of keeping privileged administrative accounts separated from normal user accounts. Indeed, one reason that older versions of Windows were so susceptible to security issues, such as drive-by virus infections, was the common practice of setting up user accounts with administrative privileges, without having the protection of the User Access Control (UAC) that's in newer versions of Windows. (Even with UAC, Windows systems still do get infected, just not quite as often.) With Unix and Linux, it's a lot harder to infect a properly configured system.
You probably already know that the all-powerful administrator account on a Unix or Linux system is the root account. If you're logged in as the root user, you can...