I bought a Windows 11 Latitude 5300 that came with Secure Boot Off in the BIOS/UEFI.  When I turn it on it obviously doesn't recognize the GPT installed and then goes into a quick Memory Diagnostics check which I escape out of.

I don't understand how they installed Windows 11... but with all this secure boot certificate talk about Windows 11 I wanted to bring this notebook into compliance.

Turning back the secure boot checkbox simply allows the notebook to boot again.