well... not being able to know much more then that.. i would say maybe depends. has this happened b4, has there any problems , like dropped or exposed to any moisture or any sort..?
I did have an xbox that if moved, or turned a certain way it would power off..and some times wouldnt come pack on.. when i finally opened up the back i noticed on the circuit board a black spot, where it must of gotten too got.. burned through the mobo.. now guess depends on ur xbox version here is a pic
http://www.brokenxbox360.co.uk/wp-content/...11/xbox-top.jpgthat is the style of my old power supply on the mobo.. and i guess maybe from pushing power plug in too much or being moved around, some sort of stress happens will cause one of the terminals to burn threw.. im sure mine wasnt the only one to have this happen.. i got around it just by using some tin foil, and fitting a very small piece wedged into the mobo, but yet not too low as to make contact with the bottom of the case.. that seemed to keep it a live..
but i cant be sure u have the same issue as me.. but get the top off, and check inside, around the power source.. unplugged of course ! see if u notice any corrosion or burnt spots near the terminals where the plug fits into