If it doesn't boot backups then it probably something with the chip. either a wire that came off or something or the firmware is corrupted. I would go more for a chip problem as the firmware should reset and boot the upgrade disc if its just a firmware issue. If it's giving the black screen, then its somethign with the bios wires or the chip usually. If you can take it apart or look inside, there is a light on the chip that gives install info. If it's solid, then it's a bios issue. If it flashed on and off but disc don't read, then it's usually a dvd/cd controller wire problem.
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