Dell Precision M6400 power issue (won't boot)

My laptop stopped booting a few weeks ago out of the blue. One minute i'm loading up Diablo III, I turn around for a minute and next thing you know, the laptop is off. I try to turn it back on but no dice. I noticed that the light on the power brick was off so I unplugged and plugged it back in, which made the light come back on. However, when I went to turn it back on, the hdd light, power light, and power button flashed once quickly and all went out along with the bricks power light. No boot whatsoever, just a quick flash.
So I trolled through a bunch of forums and came to the conclusion that it was a motherboard issue, since that seemed to be the same problem that everyone else that I had found was having. So I ordered a new mobo and installed it just today.
This is what I was greeted with much to my dismay:


This was a used motherboard I got from ebay, but it had stated it was pulled from a functional laptop and the seller had nearly perfect reputation. Could I have just been unlucky and got another dead board or could my problem be elsewhere? like say, the power brick or some other component. The power brick worked just fine for a few days before, could the power brick have gone bad and fried the motherboard somehow and then fried this new one when I plugged it in?
Any help is appreciated, this is my only laptop.
thank you

TL;DR
suspected motherboard broke so I replaced it and the new one is doing the same thing, could it be another bad board or something else?