Don't you just love computers! Fickle creatures at the best of times.
I got a Corsair H80 CPU cooler, good bit of kit, easy to fix...although there aren't references to where certain cables are supposed to go and you have to watch the youtube video!
I see that you have the H80, nice bit of kit as long as you only want to liquid cool the CPU. Have you added some hose clamps to the connections though as they do have a tendancy to come loose and leak especially if they are stressed or moved at all. You can always use cable ties if you have trouble getting pipe clips on them.