Seems the grub that centos-5 installed didn't quite manage to get your fc7t2 boot option right, see details inline below.
On Thursday 15 March 2007, Styma, Robert E (Robert) wrote:
To test CentOS 5, I loaded from DVD adding it to a system at home running Fedora Core 7 T2.
Partition Layout is: /dev/hda1 - / for the RH7T2 system /dev/hda2 - /home /dev/hda3 - swap /dev/hda4 - extended /dev/hda5 - / for CentOS 5
...
The CentOS grub.conf on /dev/hda5 looks like:
...
title FC7T2 rootnoverify (hd0,0) chainloader +1
This piece of grub config is not right for your FC7T2 install. It assumes that there is a 2nd boot-loader living on /dev/hda1 (hd0,0 in grub speak). Change it to something more like (you'll have to find the exact names and paths yourself):
title FC7T2 root (hd0,0) kernel /boot/vmlinux...fc7 ro root= ... initrd /boot/initrd-...img
good luck, Peter