Greetings,
Welcome to the forum.
I am not a HP employee.
A no boot scenario can be a bad HDD or a corrupted MBR.
A passing HP Diagnostics result suggests the MBR may be corrupted.
Something may have happened prior to this error message if the HDD is okay. Can you recall anything?
Windows feature updates can cause this.
Try tips found at this site (Link).
It is still possible the HDD may be in trouble.
Regards