T450s Intermittent system hang/boot issue

[Sultan_of_Sass]

I purchased the Thinkpad T450s this December and so far I have had no problems. I have done an upgrade of the HDD only, which was replaced with a Samsung 840 SSD. My pad had a very slight fall (less than a foot) which caused it to hang (first time ever). I attempted to reboot the system to find that it wouldn't reboot. I then attempted to boot into the BIOS/Boot menu only to find it wouldn't. The machine would hang on the splash screen and do nothing else.
As a last resort I removed the back-plate (disconnected the internal battery manually before proceeding) and re-seated the SSD and spare M.2 drive. The system then booted without issue as if nothing had happened(no error messages/prompts).

I assumed at the time that an internal drive had become loose only for it to occur a second time last night. I attempted to open Office 2013 only for the system to completely freeze, no sound, no beeps, no error codes and no mouse movement. I attempted to reboot again only to have the same issue as before, would hang on the "Press enter to interrupt boot" and a beep when pressed, but nothing would happen.

I performed a Lenovo extended system test (the one found in the BIOS), and 2 RAM tests and they all came back clean.

Is it possible an old drive could be causing the system not to boot into BIOS?

Thanks