I'm not sure whether it really is the same thing or not, but I had the same > thing with my 7VAXP Ultra board. When I plugged the power lead in the back > it would boot up. I found the problem in the BIOS. There's an option in > the Power management Setup menu called "AC Back Function" which I found, if > set to "Soft-Off", solved the problem for me. I'm not sure if you board's > BIOS has this function, but if it does try it and hopefully that will solve > the problem.