It is a pleasure to help you. I understand your system is not posting, nor booting after shutting down the system and there is no video even using the embedded graphics of the board. I suggest you verify if it is possible to get into BIOS menu using the minimum configuration, using 1 piece of memory, no hard drives, and any other external device.
Let see if you have video.
Additionally, verify how the UPS and the outlet are working.
If the problem continues, please reply with your system configuration; processor model, brand name, and model of memory; please let me know the color of the LED lights of the power supplies.
Please add the PBA and Serial numbers of the motherboard.
Please let us know if you need further assistance or if I can close this case. I will attempt to contact you again within 48 hours if we do not hear from you, the case will be closed.