cpu or motherboard fried?

onehans1982

Honorable
Aug 4, 2012
7
0
10,510
i have again i guess is fourth or fifth laptop (different brands/models) to repair and same issue:
it does not boot(black screen no sound-regard of removing battery, memory, hdd. checking on other screens {vga, hdmi}) and switch itself off in about 20sec. does anyone had same issue? is it CPU or Motherboard related?
 

onehans1982

Honorable
Aug 4, 2012
7
0
10,510
yes i did remove memory, battery, hdd mobo does not give any sound of missing parts(its undusted with commpressed air and not overheating in my opinion so applying new paste i will leave to last)
i guess is motherboard but would like to be sure that is not other way round and had to spend money on CPU too