Why does the computer turn on, but neither the OS nor other hardware boots?

Question

Iron

Hello. I have a problem. I hope they help me here. In general, for the sake of testing, I compiled a program in C ++, with a single line system ("shutdown -s -t 0");, the computer turned off. When I tried to turn it back on, the mother indicator showed FF, and that's it. The computer works, but the equipment and OS are not loaded. I pulled out the bios battery, pressed the reset button, but nothing. As it was ff and remains. In general, I really hope for your help and understanding.
Windows 10 OS, fully AMD computer, amd fx 7800 processor, mother msi ms-7640
Thank you in advance and good luck to everyone!