Here is a list of steps that can help fix a missing or corrupted boot file:

1. Ensure that all cables connected to the system are secure.


2. Check to make sure that the system is set to boot from hard drive first in BIOS/UEFI.


3. Check to see if BIOS/UEFI has been updated, and that all available updates have been applied.


4. Test the hard drive for errors using a hard drive diagnostic tool specific to the system Manufacturer.


5. Re-install the operating system.