Originally posted by SuLinUX
right, here's what happened.
The 2.6 was running but with no devices installed, sound, LAN, so what should I do from there?
What did I do wrong as it didnot boot first time and had to edit GRUB /boot/vmlinuz.old to load my old kernel.
The 2.6 kernel uses some modules with different names than the 2.4 kernel, so your setup will not be able to load the correct modules from modules.conf. The new modutils has a script to build the new format file, modprobe.conf, that translates many module names, but in alot of cases you'll have to find out what they are and load them manually (or edit init scripts).
You may find a working suse 2.6 rpm repo, there are several RPMs available for Fedora. This would at least let you use the default config they included as a base for your custom build.
Did you configure the initrd for your system (if its needed.. a boot problem is often this step). This is a very helpful description of the process: http://kerneltrap.org/node/view/799