Ok that constant booting cycle is happening to me too. Yesterday i went from a running 425x9@1.5vcore with my shiny new q6600 to everything standard (except for vddr wich i left @2.2v). Since then it starts, stays on for maybe 2 secs, shuts down, and then everything again. If i don't kill the power it does so all day. I already tried everything, it still happens even if nothing is on the board besides the cpu... i'm out of ideas by now.