How do I change my desktop configuration?

Generally the X server configures itself during installation. Sometimes though you can run into problems. Say you replaced your video card, or changed monitors. You can get funky fonts or a blurry screen which may make you think you hit yourself on your head.

You'll need to reconfigure X:
Applications -> System Settings -> Display

or to run "system-config-display" from the command-line.

This is a RedHat/Centos command.