a few posts ago i sugessted this:
Oh and also, in looking back at your first post, i see you considered booting off your restore disk? Try to, you have nothing to lose, if it boots, it will just stop on a menu and you can exit out of this proceedure not affecting anything on your computer. It will just verify if the computer is finnishing post. Do you know how to set the boot priority for the CD drive , so you can boot off the cd?