I'm having a very similar problem with a Dell Inspiron 8100 (GeForce 2 Go). I recently upgraded my kernel and packages from 2.4.7-10 to 2.4.9-34, which brought about the problem. I had x running just fine in the past on the 2.4.7-10 kernel. I've checked, rechecked and checked again my XF86Config-4 file, as well as tore through the linux drivers README @www.nvidia.com.
I also updated the nVidia drivers and kernel from -2880 to -2960 (I remembered to remove the old GLX rpm, too, before starting this).
In short, the NVdriver isn't getting loaded, and it's nowhere to be found on the system, apart from a directory in the 2.4.7-10 kernel modules section.
Help! I've tackled som e pretty nasty stuff on RedHat in the past, but this one has me stumped.
Thank you for any informaiton provided.