If you have managed to break your X configuration somehow and cannot enter X anymore, you can use xfdrake from the console to re-configure X. Simply, use the su command to become root and type XFdrake.
Using xfdrake is no different than from the graphical environment except that you might not have a mouse pointer and nice icons. To move down you have to press on the right or down arrow keys on your keyboard; to move up you have to press on the left or up keys on your keyboard. You can also use the Tab key to move among the different options/buttons. The text on the currently selected button/option will be highlighted with a different color; press the Enter key to activate it.
Please refer to Section , “Controlling the Graphical Configuration” for instructions on its usage.