Thanks for the reply Dan

Here is my menu.lst entries.
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd1,0)
# kernel /vmlinuz-version ro root=/dev/hdb2
# initrd /initrd-version.img
#boot=/dev/hda
default=3
timeout=10
splashimage=(hd1,0)/grub/splash.xpm.gz
title Fedora Core (2.6.9-1.3_FC2)
root (hd1,0)
kernel /vmlinuz-2.6.9-1.3_FC2 ro root=LABEL=/ rhgb quiet
initrd /initrd-2.6.9-1.3_FC2.img
title Fedora Core (2.6.8-1.521)
root (hd1,0)
kernel /vmlinuz-2.6.8-1.521 ro root=LABEL=/ rhgb quiet
initrd /initrd-2.6.8-1.521.img
title Fedora Core (2.6.5-1.358)
root (hd1,0)
kernel /vmlinuz-2.6.5-1.358 ro root=LABEL=/ rhgb quiet
initrd /initrd-2.6.5-1.358.img
title Windows
rootnoverify (hd0,0)
chainloader +1
I'm pretty sure I know which entries to remove, do you think it's worth it? Your suggestion about leaving an entry as a 'fallback' seemed like a good idea. I'm really only doing it improve the appearance of the boot menu. I've been booting with the new kernel for a while now and it seems fine.
Anyway, thanks again.