I've seen this happen before but I'm not too sure as to a potential repair route.

I'm working on a HP Pavilion 775y desktop computer. The heatsink that cools the northbridge popped off so it's doing all sorts of funky stuff. The mounting posts for the heatsink appear to be soldered to the motherboard (it's a black plastic shim with a metal ring extending out of the top that anchors the heatsink mounting arms down). Now one of the mounting posts is completely missing. I searched high and low through the chassis with a flashlight and a set of fine needle nose pliers and I've pretty much disassembled the entire case so it's nowhere to be found. The thing that baffles me is what kind of fix is there for this? Can I just get a new mounting post and install that or is this considered to be a trashed mobo?