cpu repair

Hi i have a weird reading if anyone can help me on the CPU high side mosfet but normal 5.1V on 2 other low sides (2 +2) if you can help me nail this down? 9/10 times the screen stays blank but ALL times when i turn on, lights, fan, 5, 3.3, 1.8, .8V ect ON all over the board so good and i already...