That has happened to me far more times then I would like to admit. usually its something with the prep job I did, CPU mounting or some dumb thing like that.
For many boards I have run when things stay cold for to long some IC's start acting up and thens when I lose my OC's and things start falling apart.
A rule I made for myself when running stuff, is never get things going good and they say ... ok this is great now, I can pick this back up tomorrow... HAHA ! never works like that.
