User groups and changing permissions

:confused Does anyone know about User groups and names (when you right click on a folder) or environmental variables? I also would like to know how I get "special permissions" again as the administrator on my computer. I keep seeing User Groups called Interactive, System, Administrators, and the mine. Once in awhile, one of the User Groups (for example, Interactive, will disappear). Is this something I need to be concerned about as I didn't create the User Groups except my own. And how do I get my administrator privilege rights back to me. Thanks... Pls see attachment for example of what I'm seeing... Thank you!

 

Hi, Thx. It's Windows 7. Used to be Windows XP awhile back.