Laptop stuck on Speed Mode

I got a SONY VAIO PCG-6W2M it's known for its faulty nvidia GPU,so mine already don't work with it (in performance mode) So I always use it on Stamina Mode (intel GPU).

But last time (after my brother messed with it) when I turn it on the performance indicator LED turns ON as well even if the switch is on Stamina Mode and the screen turns black (turns ON but black)

I think it's a currupted BIOS because I already had a simmilar problem with another VAIO and ended by flashing a new BIOS. After I tearedown the laptop following the steps on Sony Vaio VGN-SZ120P Teardown but I couldn't recognize the BIOS chip or the motherboard reference and version.