At a guess, I'd say there's a self-resetting breaker that's tripping, likely meaning something is drawing too much current. Unfortunately tracking down the source of that draw could be very involved and probably best left to a repair pro. (There's a slight chance that said breaker is defective as well, and you could try finding and replacing that... I WOULD NOT recommend bypassing it though, as if it IS working properly, that means something else is seriously wrong).