The error that you are getting (PXE-E61:Media test failure, check cable) happens when the motherboard is not detecting the hard drives, the hard drives are defective or the SATA ports are damaged.
Since you mention that you cannot access the BIOS by pressing F2, try moving the BIOS jumper to position 2-3 and then turn on the system that should force the system to go to the BIOS in maintenance mode, and make sure that the "Boot to Network" is disabled, that will remove the error (PXE-E61:Media test failure, check cable).
There is a possibility that damaging one of the SATA ports all other SATA ports will not work.
I have the same problem: "Erro Falha de teste de mídia PXE-E61 (PXE-E61 Media Test Failure)".
I try to disable "Boot to network", but when I start again I've the same problem, then I checked the "BIOS setup" again and I see that the "Boot to network" is enabled. I disable it, and it enable by itself automatically. What can I do?