Motherboard/CPU dead?

[raygunpk]

I helped my cousin install a fresh copy of Windows XP on his computer, everything was working fine. Then he plugged in his USB flash drive and the whole system crashed. It was from Japan, and it has only the slot for data and none for the ground...so it is super thin.

Now after booting up, there is no BIOS beep, no video, no POST.

I've tried:

-Pluggin only necessary items
-Jumper resets
-Swapping CMOS Batteries with my working one
-Swapping PSU with my working one
-Booting with different RAM in different slots, and then with no RAM at all

Haven't tried swapping vid cards, but at this point I'm coming to the conclusion that motherboard is dead.

I can't swap CPU chips because mine is different, so I'm not sure if it's dead or not either.

Is there any surefire ways to determine if the mobo/cpu are gone for good?
Also, how can a USB flash drive kill the motherboard (if that is the case) ?

Thanks

 

[Roguestar]

I can't think of how the USB stick would possibly be related. Maybe it's just coincidence. Have you tried plugging in the motherboard to the CPU with RAM and nothing else in it and see if it powers on the fans?

 

[raygunpk]

Yes I have tried that, the fans power on just fine.
How would I go abouts checking the CPU to see if its dead or not either? I have no other hardware here to switch around.

 

[iluvdeal]

It could have been ESD from the USB drive to the PC. I did some testing in the past where I used this type of gun which emitted ESD pulses, one of the places where the computer would shut down when I applied the pulse to it was the USB ports. I was able to power it back up each time though.

 

[raygunpk]

I can't boot up this time sadly!