asus GL503E blue screen error

[ashiq]

I have this asus GL503E showing blue screen error.When i check the board the core area supply section getting really hot. it is a 3 phase core supply .on one of the phase the lower gate of the fet (PQ99) gate having no pwm it is low condition.all other 2 phase lower and upper gate have the pwm. I have changed the "PU6"and the fets still same any solution.