Hi there, my laptop will not boot. I press the power button, light comes on. Fan will start. It does not appear to do a POST. Screen stays absolutely black. I cannot get into the BIOS. There is no output from the HDMI so I am assuming the screen is OK. I have swapped the memory about and it has the same issues. I have also tried holding power button for 30 seconds with no power/battery. It's a Samsung 350v5c which had Windows 8 and was then updated to 8.1 then 10. Any ideas? Many thanks.