Ok, I give. My computer will not boot up when I have a second SATA or IDE drive installed. Used to work fine but stopped. Second drive is fine, nothing wrong. Primary boot drive will boot in any SATA slot.
I even formatted another drive by itself, installed the OS but it won't boot up to finish the install. This is really weird. Took it out, installed the boot drive and came right up, no problem.
I attached the second drive as a USB drive with a kit and I can see my data and access it.