Motherboard damaged & replaced, hub & audio interface destroyed

Hello,

I was hooking up a desktop computer. It was working fine. I came back to it a half hour later or so and noticed the monitor was dark. The computer was no longer working. The power buttons were unresponsive. Every time I plugged the computer in, the fan spun but no self check, beep, bios screen or load to windows.

I took it to a repair shop and had the motherboard replaced. The computer works again.

As I was trying to set the computer up again, I noticed the usb 2.0 hub no longer works. I then noticed that my usb audio interface doesn't work either. These devices were hooked up to the computer when it died.

I should note that I had the computer connected to an Eaton surge protector. I don't remember it raining, storming or the lights or power flickering. I did not hear the surge protector's alarm go off.

There was also another computer running at the same time in the same room with no damage to it or its peripherals. It was connected to another power outlet and another surge protector.

I'm upset that I have to throw hundreds of dollars away replacing devices I already paid for including the motherboard, hub and audio interface.

I am also concerned that this kind of incident may occur again, destroying more of my expensive belongings including the devices I just replaced, other computer and musical gear, and other electronics.

1) What might have caused the motherboard, the hub and audio interface to all be damaged?

2) How might I figure out what happened

and

3) how can I prevent it from happening again in the future?

Thanks a lot Everyone!