Bring me up to date, is this a new install of RedHat?
When you login as root, you get the Gnome desktop OK?
If so, did RedHat format the partition (did you choose to format the partition) when you switched distros, or just overwrite the partition with the RedHat install. This is an important distinction, as you should always choose to format (wipe clean) a partition, not try to overwrite it, uless this was a RedHat upgrade.
If RedHat completed the install, the cd should be OK, but the issue may be if you wiped the partition clean (allowed RedHat to format the partiton, not just set the mount point to /) during the install.
It sounds like the /home/user directory, probably where the Gnome user files and settings are stored, is messed up.
This install is all on one partition, or did you choose multiple partitions during the install (allowed RedHat to make a /, as well as home, var... directories)?