I have slack10.1 and upgrading from kernel 2.4 to kernel 2.6.11
I did the following after having the source file in /usr/src

First I made my default vmlinuz to vmlinuz.old both in /boot and /etc/lilo.conf

Then I started my upgradation as follows:

# make menuconfig
(as I hav my fs as resiser fs, I included it in my .config file)
# make bzImage
(then I copied this from arch/i386/boot/bzImage /boot/vmlinuz

# make modules
#make modules_install
# cp System.map /boot/System.map

I had /lib/modules/2.6.11.Therefore I did,

#mkinitrd -k 2.6.11 -m reiserfs
(Now, here it said " #WARNING could not find module reiserfs....I donno why though I have included it in my .config as module..as I said...anyway I proceeded)

Then I edited(i.e., added) my /etc/lilo.conf
as
image=/boot/vmlinuz
initrd=/boot/initrd.gz
root=/dev/hda7 (...hda7 my linux drive)
label=NewLinux

But, after all these, when I rebooted my comp., in the boot loader the label of my new kernel (i.e., NewLinux) did not come up.Only the previous version is there and thus...gets booted into the same 2.4

can someone suggest what could be wrong?

I have to ask... did you "/sbin/lilo" after you modified your lilo.conf file?

yeah it works when i do #/sbin/lilo

thanks
arun