1) find something like that
label="Red Hat_<old version No.>"
and delete it
2) find and change label="Dos" to label="Windows XP"
then save changes and as root type at console
if using grub, find something like /boot/grub/menu.lst or /etc/grub/menu.lst or similar (i don't know how it is in RH)
1) find something like that and delete:
title Red Hat_<old version No.>
kernel /boot/vmlinuz root=/dev/hda3
2) find something like that and change the title