You might want to tell people how you did the upgrade...via installation CD?
When grub comes up, does it give you any options?
By nothing else would work, what did you try, and what was the result? Any errors displayed?
You might want to change the title to something like "Computer hangs on grub after Fedora 8 -> 9 upgrade"
check out the 8 -> 9 comments here (if you used yum to do the upgrade):
When you did the upgrade, did you replace the bootloader or not?
If you used a installation CD, you should be able to boot from it in rescue mode