Will not boot operating system even with optical drive.

I bought this MBP with no hard drive, question mark would illuminate on gray screen. I was hoping this indicated the logic board was OK and it was looking for the hard drive.

I installed an OEM Fujitsu SATA drive(used) and ribbon cable. It still would not boot or recognize the drive even when trying to boot using the install disc, however the hard drive is running.

It no longer showed the ? when trying to boot. I checked the RAM and found that it was not fully inserted, but that did not take care of it either. Now every time I try to boot I get the message telling me to shut down and restart.

I have tried every command I have seen on this forum always with the same result.(C, V, Shift, T, zapping PRAM, command PR) I have tried option boot as well.

I could have a bad hard drive as it was used, the RAM could be bad as it is Korean(Hynnix), or I likely have a bad logic board. I would like to eliminate all other possibilities before contemplating logic board replacement, but I do not have extra parts to switch out.

Also, the optical drive will not eject my install disc.

I would really appreciate your help, and thank you very much for this forum.