I've tried everything I could: holding power button, reseating RAM sticks, fn+F7, swapping HDD and HDMI (gives me "no signal" message), none of which worked. My laptop is Sony VAIO VPCCEE2E1R from 2010. Any idea?
You'll hate me for this but I see all sorts of small things that lead to big problems. One of them I've been called out to a blank screen and found that someone had turned the brightness slider all the way down.