I'm sorry I didn't respond earlier, I lost the post. Anyway, I read your initial post again, and after you stated that reconfiguring X didn't work, you might want to verify that you have the right video module (driver) installed on your system. You can do a search on www.google.com/linux
for your video card make and model (chipset if you have it). There should be something out there to tell which module you need. After you find out what module you need, type the following at command line:
This will give you a list of all your modules you have running on your system. If the correct module is loaded for your video card, we need to investigate further. If not, try typing the following:
You'd type the above with the correct "modulename" and without the <>'s in there too. If it cannot locate the module, then you'll need to find it online and download it. After you've got it downloaded, you'll need to install it. If you need help with this, let us know and someone who uses RedHat will be able to walk you through it.
If you don't get any errors after running modprobe, you should try starting X again and see if it works. If not, it could be the refresh rates you assigned to your monitor. Check your monitor's documentation or search for it online to get the exact horizontal and vertical refresh frequencies.
If it keeps failing, try to post any errors you find in /var/log/XFree86.0.log and hopefully we'll be able to make heads or tails of it. Hope this helps.