Computer showing no signs of life, psu working.

[Coolbrandonr]

So I was being foolish and had my computer on while Installing a wifi/bluetooth card. I had the card intstalled in the PCI slot when I went to plug in the power cable into the usb 2 expansion slot, the computer immediately shut off. The computer now will not turn on and is giving no signs of life. Ive tested the power supply and It's functional; Im assuming I shorted out the mobo, but I have no way of testing that or any way of testing the other components.

 

[clutchc]

Breadboard the system. Need to know the system specs. But if your system has a CPU w/iGPU, Connect just CPU/cooler, RAM, PSU, monitor. Disconnect everything else, even the case's FP wiring. Start the system by momentarily shorting the two pins that the case's power switch would connect to. If nothing, then the board is probably toast.

 

[Coolbrandonr]

Yep the pc still wouldnt start after disconnecting everything except the cpu/cooler, psu, ram and monitor. so I can safely assume that the mobo is fried? I have an i7 7700k, 8g of ddr4, a (thankfully)50$ msi motherboard, and an msi R9 290

 

[clutchc]

Yep the pc still wouldnt start after disconnecting everything except the cpu/cooler, psu, ram and monitor. so I can safely assume that the mobo is fried? I have an i7 7700k, 8g of ddr4, a (thankfully)50$ msi motherboard, and an msi R9 290

Well, it seems to indicate that, yes. You might try again when the board is removed from the case and set on an insulated surface just to be sure it isn't in some weird way case-related. And connect the KB too this time.
Btw, I'm still trying to understand what you meant by "I went to plug in the power cable into the usb 2 expansion slot". Also, what wi-fi card and what motherboard are we talking about here.

Did you test for voltages when you tested the PSU, or just do the paperclip test to see if the fan started? Not sure what you meant by that above phrase, but if you shorted or grounded one of the +12v, -12v, +5v or +3.3v circuits, the PSU may still 'run' just not put out one of those voltages anymore.