Most likely your problem is with the nvida module.
I had the same problem when installing RH8 and here is how I solved it, it might help you, or someone might have a better way.
I downloaded the nvidia driver from http://www.nvidia.com/content/drivers/drivers.asp
Since I couldn't start a terminal because I foolishly installed redhat with graphical login as default, I used an old Mandrake installation disk in rescue mode (My redhat 8 disk has a broken rescue mode). I mounted the Redhat boot partition as /mnt/disk and ran emacs to edit /etc/inittab
chroot /mnt/disk /usr/bin/emacs /etc/inittab
changed the default runlevel by editing the line
saved the file in emacs by ctr-x ctrl-s and exited by ctrl-x ctrl-c
Maybe I could have used telinit instead.
After rebooting, installed the nVidia driver by typing
I was prompted to accept a licence agreement and then given the option to download the latest version from ftp, I said NO here because it is not necessary.
The next step was to edit /etc/X11/XFree86Config. The driver installed a sample file named /usr/share/doc/NVIDA/XF86Config.sample.
After backing up the original XF86Config I took this sample file, changed the FontPath to "unix/:7100" and added the option "dpms" to the monitor section, and saved it as /etc/X11/XF86Config.
Typed "startx"... and it worked.