Before doing anything, try this. It worked for me.
Connect to an external screen (hdmi or vga)
spam F2
Reset your BIOS to factory
save and restart
mine booted on the laptops screen rather than the external after that.
Before getting that fix I tried taking out the battery and power together and also just opening and closing the lid a lot (which for some reason worked at one point) this problem seems persistent though, along with the overheating....