XPS 15 9550 VERY strange drive issues. Contradicting info

I am having a problem with my XPS 15 9550 i5 fhd. I recently took out my 32gb m.2 and installed Windows on a 2.5 inch hard disk. It worked fine for about a week but was giving me blue screen Critical_Process_Died until one day it wouldn't boot at all and gave me 'no bootable devices found'.

When I go into bios under system information, shows that no drives are connected > Primary hard Disk {none}

When I boot into diagnostics it passes all tests AND my ssd is shown as connected and functional

When I press f12 and boot from windows boot manager it gives me a black screen

When I try and boot to the windows USB and use diskpart. My drive shows up well all volumes and partitions are as they should be.

I can even select different boot options/efi files under bios even though it says no drive is connected but non of the efi files take me into windows. Just give me a black screen saying no boot able devices

I have tried using CMD to fix boot files but I still get no boot.

Tried a CLEAN reinstall of windows but that STILL would not boot

My SSD is not failing as it worked fine in my other system and disk scan shown no bad sectors

I am thinking this is some kind of strange hardware issue in the laptop. All cables are firmly plugged in I opened the back and checked