Does it freeze completely? or does the screen just blank out? Does it respond to keyboard input? you know, can you hit the caps lock button, numlock, or scroll lock buttons to make the lights on the keyboard flash on and off?
If the computer is not completely locked up try switching to a console display. Use crtl-alt and the f(1-6) buttons to switch...
If you have a different computer at home and they are both hooked up to a lan try ssh'ing or telnet'ing into the Redhat box.
If you get command line access to the box try reconfiguring X using XFree86 or xf86config or whatever, or/and try disabling graphical login using linuxconfig.
You know, stuff like this is why I don't use distros like Redhat. Normally this would be a easy fix if X failed to startup.. It would crash and give a nice little error on your screen saying what went wrong. Their is so much that can go wrong in configuring and loading a gui interface that it should be disabled the first time you need to login after installing a new OS. What is so hard comming up with a little freindly message at command line login prompt saying. "Please use your root account and password to login the first time". Then you login and it says, "X windows should of already been configured for you, please type startx and press enter at the prompt, if it fails to start please read our X windows troubleshooting guide by typing helpx and pressing enter", Then when X starts it comes up and says "Alright, it looks like you newly installed version of X windows is completely operational. If you want a graphical login screen from now on please click the yes button, if not go ahead and cancel this message". Now that would actually be helpful!
Now if your computer is completely locked up you may need to find a way to get into your harddrive... Can the installation disk be used as a rescue disk? I am not to sure about redhat 9... try to edit the /etc/X11/XF86Config file by hand if you know how to do that... or see if linuxconfig works or whatever. I just not that familar with RH9 to give specific advice on it..
