Lenovo G40 and G50 switching on but no display

[Takura A Chatikobo]

I have been getting lenovo g40 and lenovo g50 that are switching on and no display. i have tried reflowing but it seems lenovo has put a special type of glue that insulates the balls when you reflow and sometimes solder balls would come out. if there any solution to deal with this special type of glue. i am however trying to avoid the process of doing a reballing or fitting a new chip. Please help