'Dell Latitude with Win10 suddenly not booting: "Media test failure, check cable"

Hi all, 

I've been hunting through discussions on this forum and can't seem to find a case of this that fits my computer's specs to provide a real solution. Please help!

I'm running Windows 10 on a Dell Latitude E6430 with an IntelCore i5 2.60GHz processor. She was working fine until yesterday when I got this message: 

"Intel Boot Agent v1 .3.81
(c) 1997 - 2011

PXE-E61: Media test failure, check cable
PXE-M0F: Exiting Intel Boot Agent.
No Boot Device Found. Press any key to reboot the machine_"

So I tapdance all over the F2 key to get to BIOS on the next reboot. My NIC is enabled w/PXE. I try enabling the UEFI Network Stack and reboot. Same error. 

Next, I try switching the NIC to just "enabled." Now, the only message I get is one lonely line of text that reads, "No boot device found. Press any key to reboot the machine"

Fine, Dell. I see how it is. I switch my Boot List Option from Legacy to UEFI. When I click "Add Boot Option" a window pops up to inform me "File system not found!" I try a reboot anyways. Now I'm getting a message that says, "No bootable devices -- Strike F1 to retry boot, F2 for setup utility. Press F5 to run onboard diagnostics."

Diagnostics is trying to tell me that there is no hard drive installed. Am I missing something here? Can anyone help me fix my little homie?

Thanks. x