BIOS no longer detects M.2 PCIe SSD after disassembly

I have a Dell Latitude 5400 that I am trying to do a fresh install of Windows 11 on.

The system was detecting the M.2 PCIe NVMe SSD normally prior to shutdown. I powered the laptop off completely, unplugged the charger, and disconnected the battery. I then removed the M.2 SSD to inspect the internal components and reinstalled the same SSD back into the M.2 slot.

After reassembly, the BIOS no longer detects the M.2 PCIe SSD (SSD-0). The drive does not appear in BIOS under Storage, and no boot devices are listed.

I have reseated the SSD multiple times, ensuring it is fully inserted at the proper angle and secured with the mounting screw. I have also loaded BIOS default settings and tried switching between RAID and AHCI storage modes to force re-enumeration, with no change.

At this point, I am trying to determine whether this is most likely:

• A seating or M.2 slot issue

• A BIOS configuration or detection issue

• Or a failed SSD

Any guidance on additional BIOS checks or known issues with the Latitude 5400 M.2 slot would be appreciated.