The 2.6.20 and newer kernel abandon the Pata disk names and group Pata devices same as Sata/SCSI/USB disks.
It is highly probably the the Fedora 7 only recognise sda5 although I know some distros still support hda devices.
Before I can advise you any further I need your confirmation of the following
(1) Have you got Grub inside Fedora or you just use Lilo throughout?
(2) It is highly irregular to put the kernel and initrd in /mnt directory. Should you not have the red
# Fedora 7
image = /mnt/hda5/boot/vmlinuz-2.6.21-1.3194.fc7
root = /dev/hda5
label = Fedora
initrd = /mnt/hda5/boot/initrd-2.6.21-1.3194.fc7.img
For example My Fedora 7 menu.lst looks like this
title Fedora (184.108.40.206-41.fc7)
kernel /boot/vmlinuz-220.127.116.11-41.fc7 ro root=LABEL=/ rhgb quiet
As far as I am aware all distros put their kernel and initrd in the /boot directory, although there is nothing to stop a user to place them somewhere else.