Looks as if you have tried all the normal stuff. Could be bios I suppose, but that is rare to happen. If you have not already I would check sata (or ide) cable/ribbon and the sata port (or pins) for both HDD and optical drive. If you are sure it is not the media or the optical drive make sure there are no overheating issues - this can cause a slow or no install. I can say that 9 out of 10 times an extremely slow install is almost always 1 of three things: hdd/media/ram - run a memtest if you have not and are able. Good luck let me know how it goes.
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