You could help us to help you by giving some more information.
Is this a desktop system? A laptop system? Could we have the make and model number if it's a laptop, or the make and model of your motherboard if it's a desktop?
Is this a dual-boot system, or a Linux only system?
Did you have any problems during the install? If so, what were those problems?
Have you tried to use RedHat CD 1 as a rescue disk to boot into your installed system?
If you don't have Windows on the same machine as this RH install, I would suggest downloading a LiveCD distro such as Knoppix
and booting the machine from that. Live CD distros boot and run fully from the CD-ROM drive and don't need to be installed to the HDD, so you could use it to find out more information about what's going on with the RH system files and post it using Mozilla (when we tell you what information to look for).
If Windows is on the same system, you could use the Explore2fs file manager
to view the RH system files so we could at least begin to figure out what might be wrong, or you could boot that system from a LiveCD as well.
Please give us more information about your system, and we'll have a better idea how to proceed with troubleshooting.