Perhaps, it's something to do with ACPI,
when you boot in grub (assuming that your boot loader is grub
highlight the line with your Fedora8, type 'e' (=edit) and see if it says anything about 'acpi'
eg 'acpi=off' if it does, remove it and try to boot.
Most probably this is not the reason for it, but it's worth a try.
good luck