X wouldn't start in Foresight (Dell)

I tried to get all of the other OSes on the Dell (some on usb HDD) working today following the problems I had with the change of device numbering on the usb HDD.
Included in the changes I had to make (which included making sure the /etc/fstab in the OS -- i.e. not Ubuntu had the correct device number for /home.
In the process, I changed the kernel of Foresight from 2.6.23 to 2.6.25.
When I tried to boot to FS, it stopped without opening X. The log (/var/log/Xorg.0.log) showed that it couldn't find a screen which always means some problem in /etc/X11/xorg.conf. This time it turned out it couldn't find the nvidia driver. So I changed this back to nv and at least X now started.
So, it appeared that the nVidia module was built for the 2.6.23 kernel and wasn't happy with the newer kernel.
So, I changed back to the 2.6.23 and everything now worked using the nvidia driver.
Incidentally, I tried to build the nVidia module using the nVidia installer and the 96.43.05 driver I downloaded from nVidia. However, the build failed for reasons I didn't take time yet to understand.