I was installing a Noctua nh-d14 for my 2500k but upon booting back up, my computer would not get a video signal or show HDD usage. I don't think it is POSTing. I spent a good bit of time diagnosing things, when I decided to check out the CPU socket. To my horror, some pins were bent and out of shape. I did what I could to bend the affected pins back, but one of them looks like it is completely broken off.
Here is a picture, the red arrow points to the pin I am concerned about, as you can see it looks like it has been broken or bent in extremely. From looking at a pin diagram, I believe the pin is DMI TX .
I have no idea how this happened, but the only thing I can think of is that I tightened too hard on one side for the cooler. Is it possible this pin could prevent my computer from POST and boot up?
From what I can find online, that pin is DMI_TX #1. That means it is part of the DMI (Direct Media Interface) or the bus that connects pretty much everything together. It may not cause a no POST but you will have random issues that may be intermittent or consistent.
Most likely you will probably need to get a new motherboard.