HP desktop wont boot after thunderstorm

[Manwhoshreds]

My friends computer will not boot after a recent thunderstorm. The HP logo is displayed for roughly 6 or 7 seconds and then the monitor turns off and back on to display the logo again. This loop happens over and over again. However, I am able to enter the UEFI and make changes. I've tried booting various Linux distributions but the same thing happens. I've tried booting them in legacy mode and with secure boot disabled. I tried booting with no RAM and DID hear some beeps. I have also cleared the CMOS. I put the hard drive in another computer and it booted right up so I think I can rule out problems with the OS. The desktop is an HP 110-210 with external power supply. I believe it came with windows 8.1 and was upgraded to 10 but I would have to ask him for sure. So is it likely to be the motherboard that is fried? What else can I try?

 

[Lutfij]

If you can source a different power brick to work on your system then the external power supply can be ruled out to be faulty otherwise I'm going to have to pin the issue to a malfunctioning/semi fried motherboard. Have you tried using a Boot Drive from another machine on your HP prebuilt system to rule out that other OSes(outside of Linux) are capable of running on it?

The reason I state a fried motherboard is due to the fact that the power lead is soldered onto the board:

without any provision for an aftermarket PSU to go inside it.

You could add on an ATX PSU but you'll need to mod the chassis:

which will void your warranty though even if you got past that issue the board doesn't have standard 24/8/4 pin power connectors onboard.

Point to note, get a battery backup or a surge protector to protector any power spikes and your electrosensitive components.