What was the errror message when you went to install the nvidia drivers? Was it the kernel or XFree part causing the problem?
To use the nvidia drivers you need to use <Device "nvidia"> in your XF86Config(-4), making the other necessary changes detailed in the supplied docs.
I haven't used Redhat 7.x so I can't comment there. As it so happens I'm typing this on Debian 3.0 - works well.