We need to know what distribution you are using. In Linux land the distribution is the same as saying the brand name. Just to give you a couple of examples some popular distributions are Red Hat Fedora Core, Red Hat Enterprise Server, SuSE Professional, SuSE Enterprise Server, Debian, Ubuntu, and lots of others.
Then we need to know what version of that distrubution you are using. This may be tricky to figure out. On my SuSE machine I can click on the GUI Start Button and click on "SuSE Help Center". When that window starts I can look in the release notes. The first line says "Release Notes for SuSE Linux 9.2" so I know that I'm using version 9.2 of SuSE Linux.
The reason that we need to know these things is that each distribution has its own set of GUI management tools for system administration. The one and only thing that they all have in common for administering user accounts is the command line utilities that you are already using. I forget what the GUI system administration tool is called in Red Hat. In SuSE it is called YaST2.
As far as the version of Linux is concerned we use the kernel version number as a version. You can enter the following command to see the kernel version.
It will show you something like this.
$ uname -r
This has NOTHING to do with the version of your distribution. It is possible to add a new kernel to an older version of a distribution so your kernel version is not the same as your distribution version.