I'm guessing this is a problem with HardDrive/SATA connector.
I read that you've done all that steps but try one more time:
(I hope you have patience)
in BIOS change SATA/AHCI to IDE or compatibility mode,
unplug your drives SSD and HD.
power of comp and wait some minute.
CHECK all the SATA cables and connectors.(unplug them and plug them again)
plug back the drive with windows installation only.
start the computer.
try with DVD/USB installation as well.
I'm saying this cos I had similar problem once with booting and these steps helped.