This doesn't sound like a kernel issue to me. I doubt that the hard disk controller is messed up, but it's possible. It REALLY sounds like X is messed up.
You should boot FC5 up in console mode. At the GRUB screen, edit the boot line for FC5's kernel. Add
linux 3
to the boot arguments. Not sure if I remember where, but I think it should be right after the kernel. For example
kernel /boot/vmlinuz-2.6.16-1.2096_FC4 linux 3 ro root=LABEL=/ quiet
if not, no harm done, try again and put linux 3 at the end.
This boots you into console mode. You can see if everything is working. Log in. See if X works with "startx." If it hangs, kill it with Ctrl-Alt-Backspace, see the error messages on the console, and go fix the X configuration.
Console mode will also let you /sbin/lsmod and find out what kernel module is needed for this hard disk controller, so you can force the other distros to load it, if you so desire.