Euhm, don't want to critisise your boot disk
but maybe for a noob it is easier of he doesn't have to mount anything.
Just boot without the disk, you pc will try to boot into X, but just let it go wrong. After a minute or something the screen stops blanking and goes back to a console. When I had problems with RH8, I could log on straight away, but I've noticed that this isn't the case in Slack so if you can log on on the command line, do it. Else, press CTRL+ALT+F6 and log on there (as root).
now you need an editor... euhm try
#> pico /etc/X11/XF86Config-4
if you don't have pico, try nano and if this doesn't work take vi. Vi is the hardest editor for a noob, but no doubt that will work. To edit the file you first have to press 'i', if you want to save the file press ':x', if you want to quit without saving, press ':q!'.
I recommend you to read the manual (command: 'man vi') before trying vi, it is quite a b*tch to tame
If you edit that file, better first try some conservative resolutions like 800x600 with 8bit colors...
Once you edited the file, you don't have to reboot, just type
if boot fails, it wasn't that resolution :S.
You can also change a config file so your pc won't boot in X, this can be usefull as long as things go wrong, you can change it back afterwards. Just edit a line in /etc/inittab:
this way your RH will stop at command line prompt.
lot's of luck,