[CentOS] I've lost control of Gnome

    I tried out KDE for a while, but eventually found that it was not to 
my liking. I've switched back to Gnome, but it seems to me that options 
I used to have in the panel aren't available anymore. I'm not totally 
sure, but isn't there supposed to be some sort of Gnome (Nautilus?) 
control center? A place where I can adjust the themes, screen savers, 
and that sort of thing?
    I was sure it was there, and now I can't find it, and I'm lost about 
exactly which problem I should be fixing.
    Should there be a theme manager? If so where? I came across a theme 
switcher application, installed the RPM, and I can't find it in the 
applications menu either.

    Is Gnome upset with me for having been with KDE behind it's back?

Dave