if you can access the command line, login as a normal user (ie: not root) and try this
[user@domain ~]$ startx > startx.out > startxErrors.out
this will issue the startx command, sending the regular output to startx.out and the error output to startxErrors.out
this winformation will most likely prove useful
also: try running xf86config, i believe redhat has their own version you must use, but i'm not quite sure what it is. you should be able to find it in the more recent threads on this forum
hope this helps - good luck and penguin speed!