I've got an Alienware M9700i laptop. When power is applied either via battery or adapter, it starts up immediately (without use of the start button) with both fans going. Then, after about 1 second, you can see any lights on it go out for a split second and the fans kick off, then the whole thing starts all over again. Won't stay on long enough to post or anything. The entire cycle last less than 2 seconds, tops. And it'll just continue for as long as power is applied.
I've tried it with no HDD, no RAM, no SLI cable for the vid cards, no CMOS battery and even no processor - same thing.