Quote Originally Posted by sparks.oc View Post
I am using water cooling (Swiftech Apogee GTZ, 6 litre water reservoir etc...). I did not do anything special, everything went ok when changing the thermal paste. It just won't boot anymore. It's a big riddle to me. Nothing like this happened before in my 25 years of pc experience.
then you haven't experienced enough TIM changes in those 25 years

If you haven't already, pull it, clean everything with 99% iso and inspect your board for bent pins.