HP proDesk G3 400 sff's motherboard turns on and off (no dispay on the monitor) after bios update

[FordCliff]

My Pc was accidentally disconnected from power while it was doing a bios update which caused the problem I stated  in the subject. I've done resetting bios by ejecting battery for 5 mins, pressing cmos reset button, reseating internal components(cpu, ram, hdd, disk drive), cleaned the gold contacts and slot of ram, repasted the cpu, discharging possible residual power, swapped memory and power supply from my other working desktop but to no avail non of them fixed the issue.

I also tried to reflash the official bios by creating a usb flash drive bios recovery, I followed all the instructions stated from the HP support site ( https://www.youtube.com/watch?v=zjAZ0DTX3aI) but I can't seem access the bios due to the pc constantly powering off and on. I inserted the bios recovery flash drive while the pc was unplugged and pressed windows key + B combination before turning on the pc to initialize the flashing but yeah the pc would just turn on for a sec and fans spin and then turns off and turn on again in a loop. Is there any other way to fix this that doesn't require an external bios programmer ?

Hope someone sees this and thanks in advance.

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[Bill_To]

Hello

It seems you have done all the troubleshooting that one can do.

I would say try to reflash the BIOS using an external programmer or replace the motherboard.

Try a local PC tech to flash the BIOS. You can get the required part to reprogram the BIOS at Amazon.

[FordCliff]

yeah thought so too ,anyways thanks for the reply.