Chipped Chips

Something weird was growing in my watercooling setup so I took it apart to clean it, put it all together again but now it wont post. Lights on but no one is home.

Minimal components and all the usual stuff doesn't help. I was taking a close look at the northbridge chip and I noticed that 3 of the 4 corners are chipped. I'm thinking that could be the cause of the problem. I think I may have turned the thumbscrews one too many times and when the heatsink moved it chipped the chip.

I wanted to know how much of the top surface of the chip is dispensible. The chips don't go all the way down and I figured that the top layer is just a protective layer anyway so if it does get chipped its not a big deal.

Does anyone know if a chip might be causing this?

I've had some duron spitfires that could have all four corners cracked and would still run. I've also had an 1800 Tb that died after a hairline chip out of the side of the die.