Can you please summarize the solution as I have the same problem with FC5 box?
My kernel was the i586 kernel. I typed uname -a and only saw i686 so thought I had the correct kernel installed. I knew about the i586/i686 kernel problem under FC6 but thought I was running the correct kernel. I needed to use the long rpm command to verify that I had a i586 kernel installed. There is a previous post concerning exactly this problem and I was able to resolve my issue. However, my X hangs right before it automatically logs in my mythtv user. I suspect that it is a problem with my nvidia installation because I have a Geforce 4 4000 and need to run the older nvidia-x11-drv-96xx driver. Installing this driver didn't seem to work because when my machine boots it tells me that the driver is already installed (which is the nvidia-x11-drv driver and it doesn't work on my card). I'm going to try and remove dkms and reinstall it again. Failing that I'm just going to wipe the box and start over. It's only a FE for my mythbox. Hope this helps. -- -=/>Thom
