Latitude E7470 cannot find boot device. All diagnostics pass.

I have a latitude e7470 with Windows 10 pro. Over the summer, it was left out in the rain. I opened it up, removed the battery, and left it to dry out for a few weeks. I replaced the battery, plugged into AC power, and powered it up. I got to the Dell splash screen, then the following text appeared:

No bootable devices found
Press F1 key to retry boot
Press F2 key to reboot into setup
Press F5 key to run onboard diagnostics

I went into setup to confirm that the SSD hard drive was present. Then I ran the onboard diagnostics. All of the tests passed.

This told me the problem must be in the BIOS settings. I restored them to their default settings, which resulted in this:

Selecting "Enable Attempt Legacy Boot" does not help.

I wondered if the SSD might be corrupted. I removed it from the computer, inserted it into a USB SSD enclosure, and examined it with another computer. All the files and folders were where they should be, and chkdsk did not find any errors on the drive. This leads me to believe it is indeed the BIOS settings that are the problem.

I need to know what settings this computer shipped with when it left the factory or I need for someone who has this model to send me some screenshots telling me what settings I should be using. Please don't speculate if you can't provide me with either of these answers.

Of course I do not have any media with which to reload the OS. This computer was a refurb my wife bought at a local computer outlet. There's no factory support on it.