control panel

I not sure how to explain this, but i was having a problem with my PC a while
ago. Someone told me how to bring up this window that has some options on
it. There were boxes and they had X or check's in them. One of the options
was to Initiate media center or not depending on which box was
selected....etc It was some sort of command that you type in RUN (when you
click on the start button) or something. I cant remember how to do it?! Can
anyone help? or know what i am talking about?
.