Question PC crashes when any USB is inserted. Boots to black screen afterwards.

[Kalypana]

I have a desktop which, as the title states, will crash when any USB is connected after windows has booted, eg. iPhone charger, mouse, WiFi dongle. The computer completely freezes and I have to force shutdown on the case. When I try to restart, the connected screen doesn't register anything, no BIOS, and the keyboard doesn't light up. But about 10% of the time, the PC will randomly boot, but if I try to plug in a USB, it will crash again.
I have tried all USB ports, it is the same outcome.
If a USB is connected before startup, it will work, but it will rarely start up if multiple USB's are connected.
It should be noted that the PC is on a boat, and at one point the PC case would shock you if you touched it.
Any help is appreciated.

 

[rgd1101]

full system spec? look like there is short

 

[Kalypana]

Thanks for the reply. I don't know the full specs, sorry, i just know that most of the hardware was replaced recently and it worked to start with. How do i find out if there is a short and where it is? And how would i fix it?