1. Read the Linux Newbie Guide before you go much further - or you could end up in a bigger mess! http://dbstreams.ca/mirrors/linux-newbie/lnag.pdf
2. The XF86Config file is located in the /etc/X11 directory (# cd /etc/X11)
3. Depending on your Linux distribution and version, the relevant file may be XF86Config OR XF86Config-4. RH8.0 uses plain vanilla XF86Config.
4. Login as root, using the root password you entered when setting up the system.
5. Before you do ANYTHING, make a backup of the existing file (# cp XF86Config XF86Config.bak1)
6. You can view the file listing by:
# cat XF86Config | more
7. You can edit the file by:
# vi XF86Config
vi is quite simple to use, but it is totally different from Windows Notepad. Basic rescue commands:
When you see the file listing, press "i" and you will go into "insert" mode. Use the cursor controls (up, down, left, right arrows) to move where you want in the file. Do not try to use the mouse.
When you have finished editing, press "Esc", then :wq! to write the file and quit, or :q! to quit without saving.
7. You can get plenty of information about how to configure XF86Config from this forum. Also NVidia provide a readme with config examples.
If you look through this forum, you will see some example XF86Config files. Alternatively, take the easy way out and install a configurator like "Yanc": http://sourceforge.net/projects/yanc/
8. To start the X-server, type "startx". To stop it hit "Ctrl" "Alt" "BkSp".
9. If all else fails and you have to revert to a standard VESA driver, these tools may help you:
(ii) redhat-config-xfree86 (for RH8.0)
I hope this helps. Good luck!