Externally powered usb hub killed computer?

[MinerModi]

Hello so I actually already made a post about what happened to my pc so im sorry for having to make another one but i remebered something. So basically i have this cheap 4 usb port hub that cane be powered externally. I have had this usb hub for months now but i never had an appropriate power plug to have it powered not up until last month when i came across a spare  one. So i immediate plugged the plug in to the socket turned on my pc plugged in my yet unpowered hub and then it happened.

As soon as i plugged in the power cable into the hub the pc shut off and wouldnt turn on again so i thought of the cmos and decided to reset it and then it turned on for a few seconds and turned off again so when that didnt work i tried fully replacing it and the same thing happened when even that didnt work i suspected my brand new power supply so i tried another one to no avail. This got me really worried i replaced the thermal paste on my cpu replaced the ram but still nothing works. I am afraid this might have fried something on my motherboard but i needed to make sure and also i font know if this helps or not but after every major change i do to the motherboard like reseating a cable or something or resseting the cmos it would turn on for 2 seconds and then turns off again. Also after turning off permenantly any connected device would still recieve power through the usb ports.

PC SPECS:

I3-4150

8GB Ram

FSP Hydro G 850 W modular power supply 

Rosewill fbm 01

[Guest]

Sounds to me like you shorted out your PC. A USB Hub should not have external power like that (least not to my knowledge). Sound like one of the USB Killers just with the added step of a wall plug

[Dujith]

Powered USB hubs are normal. 

Looking at your pictures it looks like you swapped polarity on the power in and thus have +5V on the gnd pin of the USB to the PC.

[MrMcMuffinJr]

its a usb killer in disguise 

[MinerModi]

So do you think the pc is enirely dead?

If so would the ram or cpu still work?

[JeJaRaLa]

13 minutes ago, MinerModi said:

So do you think the pc is enirely dead?

If so would the ram or cpu still work?

maybe they are alive but you need to test  on another  motherboard